Taxoids, their preparation and pharmaceutical compositions containing them

ABSTRACT

New taxoids of general formula (I):                    
     their preparation and pharmaceutical compositions containing them. 
     The new products of general formula (I) in which Z represents a radical of general formula (II):                    
     display noteworthy antitumour and antileukaemic properties.

This is a continuation of application Ser. No. 08/622,011, filed Mar.26, 1996 now U.S. Pat. No. 5,847,170.

The present invention relates to new taxoids of general formula (I)

in which:

Z represents a hydrogen atom or a radical of general formula (II):

in which:

R₁ represents

a benzoyl radical optionally substituted with one or more identical ordifferent atoms or radicals selected from halogen atoms, alkyl radicalscontaining 1 to 4 carbon atoms, alkoxy radicals containing 1 to 4 carbonatoms and trifluoromethyl radicals,

a thenoyl or furoyl radical or

a radical R₂—O—CO— in which R₂ represents:

an alkyl radical containing 1 to 8 carbon atoms,

an alkenyl radical containing 2 to 8 carbon atoms,

an alkynyl radical containing 3 to 8 carbon atoms,

a cycloalkyl radical containing 3 to 6 carbon atoms,

a cycloalkenyl radical containing 4 to 6 carbon atoms or

a bicycloalkyl radical containing 7 to 10 carbon atoms,

these radicals being optionally substituted with one or moresubstituents selected from halogen atoms, hydroxyl radicals, alkoxyradicals containing 1 to 4 carbon atoms, dialkylamino radicals in whicheach alkyl portion contains 1 to 4 carbon atoms, piperidino radicals,morpholino radicals, 1-piperazinyl radicals, said piperazinyl radicalsbeing optionally substituted at position 4 with an alkyl radicalcontaining 1 to 4 carbon atoms or with a phenylalkyl radical in whichthe alkyl portion contains 1 to 4 carbon atoms, cycloalkyl radicalscontaining 3 to 6 carbon atoms, cycyloalkenyl radicals containing 4 to 6carbon atoms, phenyl radicals, said phenyl radicals being optionallysubstituted with one or more atoms or radicals selected from halogenatoms, alkyl radicals containing 1 to 4 carbon atoms, and alkoxyradicals containing 1 to 4 carbon atoms, cyano radicals, carboxylradicals and alkoxycarbonyl radicals in which the alkyl portion contains1 to 4 carbon atoms,

a phenyl or α- or β-naphthyl radical optionally substituted with one ormore atoms or radicals selected from halogen atoms, alkyl radicalscontaining 1 to 4 carbon atoms, and alkoxy radicals containing 1 to 4carbon atoms,

a 5-membered aromatic heterocyclic radical preferably selected fromfuryl and thienyl radicals,

or a saturated heterocyclic radical containing 4 to 6 carbon atoms,optionally substituted with one or more alkyl radicals containing 1 to 4carbon atoms,

R₃ represents

an unbranched or branched alkyl radical containing 1 to 8 carbon atoms,

an unbranched or branched alkenyl radical containing 2 to 8 carbonatoms,

an unbranched or branched alkynyl radical containing 2 to 8 carbonatoms,

a cycloalkyl radical containing 3 to 6 carbon atoms,

a phenyl or α- or β-naphthyl radical optionally substituted with one ormore atoms or radicals selected from halogen atoms, alkyl, alkenyl,alkynyl, aryl, aralkyl, alkoxy, alkylthio, aryloxy, arylthio, hydroxyl,hydroxyalkyl, mercapto, formyl, acyl, acylamino, aroylamino,alkoxycarbonylamino, amino, alkylamino, dialkylamino, carboxyl,alkoxycarbonyl, carbamoyl, alkylcarbamoyl, dialkylcarbamoyl, cyano,nitro, and trifluoromethyl radicals,

or a 5-membered aromatic heterocycle containing one or more identical ordifferent hetero atoms selected from nitrogen, oxygen and sulphur atomsand optionally substituted with one or more identical or differentsubstituents selected from halogen atoms, alkyl, aryl, amino,alkylamino, dialkylamino, alkoxycarbonylamino, acyl, arylcarbonyl,cyano, carboxyl, carbamoyl, alkylcarbamoyl, dialkylcarbamoyl andalkoxycarbonyl radicals,

with the understanding that, in the substituents of the phenyl, α- orβ-naphthyl and aromatic heterocyclic radicals, the alkyl radicals andthe alkyl portions of the other radicals contain 1 to 4 carbon atoms,the alkenyl and alkynyl radicals contain 2 to 8 carbon atoms, and thearyl radicals are phenyl or α- or β-naphthyl radicals,

R₄ represents

an alkoxy radical containing 1 to 6 carbon atoms in an unbranched orbranched chain,

an alkenyloxy radical containing 3 to 6 carbon atoms in an unbranched orbranched chain,

an alkynyloxy radical containing 3 to 6 carbon atoms in an unbranched orbranched chain,

a cycloalkyloxy radical containing 3 to 6 carbon atoms or

a cycloalkenyloxy radical containing 4 to 6 carbon atoms,

these radicals being optionally substituted with one or moresubstituents selected from halogen atoms, an alkoxy radical containing 1to 4 carbon atoms, an alkylthio radical containing 1 to 4 carbon atoms,a carboxyl radical, an alkyloxycarbonyl radical in which the alkylportion contains 1 to 4 carbon atoms, a cyano radical, a carbamoylradical, an N-alkylcarbamoyl radical and a N,N-dialkylcarbamoyl radicalin which each alkyl portion contains 1 to 4 carbon atoms, or both alkylportions, together with the nitrogen atom to which they are linked, forma saturated 5- or 6-membered heterocyclic radical optionally containinga second hetero atom selected from oxygen, sulphur and nitrogen atoms,said saturated 5- or 6-membered heterocyclic radical optionally beingsubstituted with a substituent selected from an alkyl radical containing1 to 4 carbon atoms, a phenyl radical, and a phenylalkyl radical inwhich the alkyl portion contains 1 to 4 carbon atoms,

R₅ represents

an alkoxy radical containing 1 to 6 carbon atoms in an unbranched orbranched chain,

an alkenyloxy radical containing 3 to 6 carbon atoms,

an alkynyloxy radical containing 3 to 6 carbon atoms,

a cycloalkyloxy radical containing 3 to 6 carbon atoms or

a cycloalkenyloxy radical containing 3 to 6 carbon atoms,

these radicals being optionally substituted with at least onesubstituent selected from halogen atoms, an alkoxy radical containing 1to 4 carbon atoms, an alkylthio radical containing 2 to 4 carbon atoms,a carboxyl radical, an alkyloxycarbonyl radical in which the alkylportion contains 1 to 4 carbon atoms, a cyano radical, a carbamoylradical, an N-alkylcarbamoyl radical, and a N,N-dialkylcarbamoyl radicalin which each alkyl portion contains 1 to 4 carbon atoms or, with thenitrogen atom to which it is linked, forms a saturated 5- or 6-memberedheterocyclic radical optionally containing a second hetero atom selectedfrom oxygen, sulphur and nitrogen atoms, optionally selected with asubstituent selected from an alkyl radical containing 1 to 4 carbonatoms, a phenyl radical and a phenylalkyl radical in which the alkylportion contains 1 to 4 carbon atoms.

Preferably, the aryl radicals which can be represented by R₃ are phenylor α- or β-naphthyl radicals optionally substituted with one or moreatoms or radicals selected from halogen atoms (fluorine, chlorine,bromine, iodine) alkyl, alkenyl, alkynyl, aryl, arylalkyl, alkoxy,alkylthio, aryloxy, arylthio, hydroxyl, hydroxyalkyl, mercapto, formyl,acyl, acylamino, aroylamino, alkoxycarbonylamino, amino, alkylamino,dialkylamino, carboxyl, alkoxycarbonyl, carbamoyl, dialkylcarbamoyl,cyano, nitro and trifluoromethyl radicals, on the understanding that thealkyl radicals and the alkyl portions of the other radicals contain 1 to4 carbon atoms, that the alkenyl and alkynyl radicals contain 2 to 8carbon atoms and that the aryl radicals are phenyl or α- or β-naphthylradicals.

Preferably, the heterocyclic radicals which can be represented by R₃ are5-membered aromatic heterocyclic radicals containing one or moreidentical or different atoms selected from nitrogen, oxygen and sulphuratoms, optionally substituted with one or more identical or differentsubstituents selected from halogen atoms (fluorine, chlorine, bromine,iodine), alkyl radicals containing 1 to 4 carbon atoms, aryl radicalscontaining 6 or 10 carbon atoms, alkoxy radicals containing 1 to 4carbon atoms, aryloxy radicals containing 6 to 10 carbon atoms, aminoradicals alkylamino radicals containing 1 to 4 carbon atoms,dialkylamino radicals in which each alkyl portion contains 1 to 4 carbonatoms, acylamino radicals in which the acyl portion contains 1 to 4carbon atoms, alkoxycarbonylamino radicals containing 1 to 4 carbonatoms, acyl radicals containing 1 to 4 carbon atoms, arylcarbonylradicals in which the aryl portion contains 6 or 10 carbon atoms, cyanoradicals, carboxyl radicals, carbamoyl radicals, alkylcarbamoyl radicalsin which the alkyl portion contains 1 to 4 carbon atoms,dialkylcarbamoyl radicals in which each alkyl portion contains 1 to 4carbon atoms, and alkoxycarbonyl radicals in which the alkoxy portioncontains 1 to 4 carbon atoms.

Preferably, the radicals R₄ and R₅, which may be identical or different,represent unbranched or branched alkoxy radicals containing 1 to 6carbon atoms, optionally substituted with a methoxy, ethoxy, ethylthio,carboxyl, methoxycarbonyl, ethoxycarbonyl, cyano, carbamoyl,N-methylcarbamoyl, N-ethylcarbamoyl, N,N-dimethylcarbamoyl,N,N-diethylcarbamoyl, N-pyrrolidinocarbonyl or N-piperidinocarbonylradical.

More particularly, the present invention relates to the products ofgeneral formula (I) in which Z represents a hydrogen atom or a radicalof general formula (II) in which R₁ represents a benzoyl radical or aradical R₂—O—CO— in which R₂ represents a tert-butyl radical and R₃represents an alkyl radical containing 1 to 6 carbon atoms, an alkenylradical containing 2 to 6 carbon atoms, a cycloalkyl radical containing3 to 6 carbon atoms, a phenyl radical optionally substituted with one ormore identical or different atoms or radicals selected from from halogenatoms (fluorine, chlorine), alkyl (methyl), alkoxy (methoxy),dialkylamino (dimethylamino), acylamino (acetylamino),alkoxycarbonylamino (tert-butoxycarbonylamino), trifluoromethyl, a2-furyl radical, a 3-furyl radical, a 2-thienyl radical, a 3-thienylradical, a 2-thiazolyl radical, a 4-thiazolyl radical, and a 5-thiazolylradical, and R₄ and R₅, which may be identical or different, eachrepresent an unbranched or branched alkoxy radical containing 1 to 6carbon atoms.

Still more particularly, the present invention relates to the productsof general formula (I) in which Z represents a hydrogen atom or aradical of general formula (II) in which R₃ represents a benzoyl radicalor a radical R₂—O—CO— in which R₂ represents a tert-butyl radical and R₃represents an isobutyl, isobutenyl, butenyl, cyclohexyl, phenyl,2-furyl, 3-furyl, 2-thienyl, 3-thienyl, 2-thiazolyl, 4-thiazolyl or5-thiazolyl radical, and R₄ and R₅, which may be identical or different,each represent a methoxy, ethoxy or propoxy radical.

The products of general formula (I) in which Z represents a radical ofgeneral formula (II) display noteworthy antitumour and antileukaemicproperties.

According to the present invention, the new products of general formula(I) in which Z represents a radical of general formula (II) may beobtained by esterification of a product of general formula (III):

in which R₄ and R₅ are defined as above, by means of an acid of generalformula (IV):

in which R₁ and R₃ are defined as above, and either R₆ represents ahydrogen atom and R₇ represents a group protecting the hydroxylfunction, or R₆ and R₇ together form a saturated 5- or 6-memberedheterocycle, or by means of a derivative of this acid, to obtain anester of general formula (V):

in which R₁, R₃, R₄, R₅, R₆ and R₇ are defined above, followed byreplacement of the protective groups represented by R₇ and/or R₆ and R₇by hydrogen atoms.

The esterification by means of an acid of general formula (IV) may beperformed in the presence of a condensing agent (carbodiimide, reactivecarbonate) and an activating agent (aminopyridines) in an organicsolvent (ether, ester, ketones, nitriles, aliphatic hydrocarbons,halogenated aliphatic hydrocarbons, aromatic hydrocarbons) at atemperature from −10 to 90° C.

The esterification may also be carried out using the acid of generalformula (IV) in the form of the symmetrical anhydride, working in thepresence of an activating agent (aminopyridines) in an organic solvent(ethers, esters, ketones, nitriles, aliphatic hydrocarbons, halogenatedaliphatic hydrocarbons, aromatic hydrocarbons) at a temperature of from0 to 90° C.

The esterification may also be carried out using the acid of generalformula (IV) in halide form or in the form of a mixed anhydride with analiphatic or aromatic acid, optionally prepared in situ, in presence ofa base (tertiary aliphatic amine), working in an organic solvent(ethers, ester, ketones, nitriles, aliphatic hydrocarbons, halogenatedaliphatic hydrocarbons, aromatic hydrocarbons) at a temperature of from0 to 80° C.

Preferably, R₆ represents a hydrogen atom and R₇ represents a groupprotecting the hydroxyl function, or alternatively R₆ and R₇ togetherform a saturated 5- or 6-membered heterocycle.

When R₆ represents a hydrogen atom, R₇ preferably represents amethoxymethyl, 1-ethoxyethyl, benzyloxymethyl, trimethylsilyl,triethylsilyl, β-trimethylsilylethoxymethyl, benzyloxycarbonyl ortetrahydropyranyl radical.

When R₆ and R₇ together form a heterocycle, the latter is preferably anoxazolidine ring optionally monosubstituted or gem-disubstituted atposition 2.

Replacement of the protective groups R₇ and/or R₆ and R₇ by hydrogenatoms may be performed, depending on their nature, in the followingmanner:

1) when R₈ represents a hydrogen atom and R₇ represents a groupprotecting the hydroxyl function, replacement of the protective groupsby hydrogen atoms is performed by means of an inorganic acid(hydrochloric acid, sulphuric acid, hydrofluoric acid) or organic acid(acetic acid, methanesulphonic acid, trifluoromethanesulphonic acid,p-toluenesulphonic acid) used alone or mixed, working in an organicsolvent chosen from alcohols, ethers, esters, aliphatic hydrocarbons,halogenated aliphatic hydrocarbons, aromatic hydrocarbons or nitriles ata temperature of from −10 to 60° C., or by means of a source of fluroideions such as a hydrofluorine acid/triethylamine complex, or by catalytichydrogenation,

2) when R₆ and R₇ together form a saturated 5- or 6-memberedheterocycle, and more especially an oxazolidine ring of general formula(VI):

in which R₁ is defined as above and R₈ and R₉, which may be identical ordifferent, represent a hydrogen atom or an alkyl radical containing 1 to4 carbon atoms, or an aralkyl radical in which the alkyl portioncontains 1 to 4 carbon atoms and the aryl portion preferably representsa phenyl radical optionally substituted with one or more alkoxy radicalscontaining 1 to 4 carbon atoms, or an aryl radical preferablyrepresenting a phenyl radical optionally substituted with one or morealkoxy radicals containing 1 to 4 carbon atoms, or alternatively R₈represents an alkoxy radical containing 1 to 4 carbon atoms or atrihalomethyl radical such as trichloromethyl or a phenyl radicalsubstituted with a trihalomethyl radical such as trichloromethyl and R₉represents a hydrogen atom, or alternatively R₈ and R₉, together withthe carbon atom to which they are linked, form a 4- to 7-membered ring,replacement of the protective group formed by R₆ and R₇ by hydrogenatoms may be performed, depending on the meanings of R₁, R₈ and R₉, inthe following manner:

a) when R₁ represents a tert-butoxycarbonyl radical and R₈ R₉, which maybe identical or different, represent an alkyl radical or an aralkyl(benzyl) or aryl (phenyl) radical, or alternatively R₆ represents atrihalomethyl radical or a phenyl radical substituted with atrihalomethyl radical and R₉ represents a hydrogen atom, oralternatively R₈ and R₉ together form a 4- to 7-membered ring, treatmentof the ester of general formula (v) with an inorganic or organic acid,where appropriate in an organic solvent such as an alcohol, yield theproduct of general formula (VII):

in which R₃, R₄ and R₅ are defined as above, which is acylated by meansof benzoyl chloride in which the phenyl ring is optionally substitutedor by means of thenoyl chloride, or furoyl chloride or of a product ofgeneral formula:

R₂—O—CO—X   (VIII)

in which R₂ is defined as above and X represents a halogen atom(fluorine, chloride) or a residue —O—R₂ or —O—CO—O—R₂, to obtain aproduct of general formula (I) in which Z represents a radical ofgeneral formula (II).

Preferably, the product of general formula (V) is treated with formicacid at a temperature in the region of 20° C. to yield the product ofgeneral formula (VII).

Preferably, the acylation of the product of general formula (VII) bymeans of a benzoyl chloride in which the phenyl radical is optionallysubstituted or by means of thenoyl chloride, of furoyl chloride or of aproduct of general formula (VIII) is performed in an inert organicsolvent chosen from esters such as ethyl acetate, isopropyl acetate orn-butyl acetate and halogenated aliphatic hydrocarbons such asdichloromethane or 1,2-dichloroethane, in the presence of an inorganicbase such as sodium bicarbonate or an organic base such astriethylamine. The reaction is performed at a temperature of from 0 to50° C., and preferably at about 20° C.

b) wherein R₁ represents an optionally substituted benzoyl radical, athenoyl or furoyl radical or a radical R₂O—CO— in which R₂ is defined asabove, R₈ represents a hydrogen atom or an alkoxy radical containing 1to 4 carbon atoms or a phenyl radical substituted with one or morealkoxy radicals containing 1 to 4 carbon atoms and R₉ represents ahydrogen atom, replacement of the protective group formed by R₆ and R₇by hydrogen atoms is performed in the presence of an inorganic acid(hydrochloric acid, sulphuric acid) or organic acid (acetic acid,methanesulphonic acid, trifluoromethanesulphonic acid,p-toluenesulphonic acid) used alone or mixed in a stoichiometric orcatalytic amount, working in an organic solvent chosen from alcohols,ethers, esters, aliphatic hydrocarbons, halogenated aliphatichydrocarbons and aromatic hydrocarbons at a temperature of from −10 to60° C., and preferably from 15 to 30° C.

According to the invention, the products of general formula (III), thatis to say the products of general formula (I) in which Z represents ahydrogen atom and R₄ and R₅ are defined as above, may be obtained from10-deacetylbaccatin III of formula (IX):

It can be especially advantageous to protect the hydroxyl functions atthe positions 7 and 13 selectively, for example in the form of a silyldiether which may be obtained by the action of a silyl halide of generalformula:

(R)₃—Si—Hal   (X)

in which the symbols R₁ which may be identical or different, representan alkyl radical containing 1 to 6 carbon atoms, optionally substitutedwith a phenyl radical, or a cycloalkyl radical containing 3 to 6 carbonatoms or a phenyl radical, on 10-deacetylbaccatin III, to obtain aproduct of general formula (XI):

in which R is defined as above, followed by the action of a product ofgeneral formula:

R′₄—X₁   (XII)

in which R′₄ represents a radical such that R′₄—O is identical to R₄defined as above and X₁ represents a reactive ester residue such as asulphuric or sulphonic ester residue or a halogen atom, to obtain aproduct of general formula (XIII):

in which R and R₄ are defined as above, the silyl protective groups ofwhich are replaced by hydrogen atoms to obtain a product of generalformula (XIV):

in which R₄ is defined as above, which is etherified selectively atposition 7 by the action of a product of general formula:

R′₅—X₂   (XV)

in which R′₅ represents a radical such that R′₅—O is identical to R₅defined as above and X₂ represents a halogen atom or a reactive esterresidue such as a sulphuric or sulphonic ester residue, to give theproduct of general formula (III).

Generally, the action of a silyl derivative of general formula (X) on10-deacetylbaccatin III is performed in pyridine or triethylamine, whereappropriate in the presence of an organic solvent such as an aromatichydrocarbon, for instance benzene, toluene or xylenes, at a temperaturebetween 0° C. and the refluxing temperature of the reaction mixture.

Generally, the action of a product of general formula (XII) on a productof general formula (XI) is performed, after metalation of the hydroxylfunction at position 10 by means of an alkali metal hydride, such assodium hydride, an alkali metal amide, such as lithium amide, or analkali metal alkylide, such as butyllithium, working in an organicsolvent, such as dimethylformamide or tetrahydrofuran, at a temperatureof from 0 to 50° C.

Generally, the replacement of the silyl protective groups of the productof general formula (XIII) by hydrogen atoms is performed by means of anacid such as hydrofluoric acid or trifluoroacetic acid in the presenceof a base such as triethylamine or pyridine optionally substituted withone or more alkyl radicals containing 1 to 4 carbon atoms, the baseoptionally being combined with an inert organic solvent such as anitrile, for instance acetonitrile, or a halogenated aliphatichydrocarbon, such as dichloromethane, at a temperature of from 0 to 80°C.

Generally, the action of a product of general formula (XV) on a productof general formula (XIV) is performed under the conditions describedabove for the action of a product of general formula (XII) on a productof general formula (XI).

According to the invention, the products of general formula (I) in whichZ represents a radical of general formula (II), R₄ is defined as aboveand R₅ is defined as above may be obtained from a product of generalformula (XVI):

in which R₁, R₃, R₆ and R₇ are defined as above, by silylation atposition 7 by means of a product of general formula (X), to obtain aproduct of general formula (XVII):

in which R, R₁, R₃, R₆ and R₇ are defined as above, which isfunctionalized at position 10 by means of a product of general formula(XII) to give a product of general formula (XVIII):

in which R, R₁, R₃, R₄, R₆ and R₇ are defined as above, the silylprotective group of which is replaced by a hydrogen atom to give aproduct of general formula (XIX):

which, by the action of a product of general formula (XV), yields theproduct of general formula (V), the protective groups of which arereplaced by hydrogen atoms to give a product of general formula (I) inwhich Z represents a radical of general formula (II).

The reactions used for silylation, functionalization and replacement ofthe protective groups by hydrogen atoms are performed under conditionssimilar to those described above.

The products of general formula (XVI) may be obtained under theconditions described in European Patent EP 0,336,841 and internationalApplications PCT WO 92/09589 and WO 94/07878, the disclosures of whichare hereby incorporated by reference in their entirety, or from theproducts of general formula (XX):

in which R₁ and R₃ are defined as above, according to known methods forprotecting the hydroxyl function of the side chain without affecting theremainder of the molecule.

According to the invention, the products of general formula (I) in whichZ represents a hydrogen atom or a radical of general formula (II) may beobtained by the action of activated Raney nickel, in the presence of analiphatic alcohol containing 1 to 3 carbon atoms or an ether such astetrahydrofuran or dioxane, on a product of general formula (XXI):

in which R₄ is defined as above and R′ and R″, which may be identical ordifferent, represent a hydrogen atom or an alkyl radical containing 1 to6 carbon atoms, an alkenyl radical containing 2 to 6 carbon atoms, analkynyl radical containing 2 to 6 carbon atoms, a cycloalkyl radicalcontaining 3 to 6 carbon atoms or a cycloalkenyl radical containing 3 to6 carbon atoms, optionally substituted, or alternatively R′ and R″,together with the carbon atom to which they are linked, form acycloalkyl radical containing 3 to 6 carbon atoms or a cycloalkenylradical containing 4 to 6 carbon atoms, and Z₁ represents a hydrogenatom or a radical of general formula (XXII):

in which R₁, R₃, R₆ and R₇ are defined as above, and, to obtain aproduct of general formula (XXIII):

followed, when Z₁ represents a radical of general formula (XXII), thatis to say when the product of general formula (XXIII) is identical tothe product of general formula (V), by replacement of the protectivegroups represented by R₆ and/or R₆ and R₇ by hydrogen atoms under theconditions described above.

Generally, the action of activated Raney nickel in the presence of analiphatic alcohol or an ether is performed at a temperature of from −10to 60° C.

According to the invention, the product of general formula (XXI) inwhich Z₁ and R₄ are defined as above may be obtained by the action of asulphoxide of general formula (XXIV):

in which R′ and R″ are defined as above, on a product of general formula(XIX).

Generally, the reaction of the sulphoxide of general formula (XXIV),preferably dimethyl sulphoxide, with the product of general formula(XIX) is performed in the presence of a mixture of acetic acid andacetic anhydride or a derivative of acetic acid such as a haloaceticacid at a temperature of from 0° to 50° C., and preferably at about 25°C.

The new products of general formula (I) obtained by carrying out theprocesses according to the invention may be purified according to knownmethods such as crystallization or chromatography.

The products of general formula (I) in which Z represents a radical ofgeneral formula (II) display noteworthy biological properties.

In vitro, measurement of the biological activity is performed on tubulinextracted from pig's brain by the method of M. L. Shelanski et al.,Proc. Natl. Acad. Sci. USA, 70, 765-768 (1973). Study of thedepolymerization of microtubules to tubulin is performed according tothe method of G. Chauvière et al., C. R. Acad. Sci., 293, series II,501-503 (1981). In this study, the products of general formula (I) inwhich Z represents a radical of general formula (II) were shown to be atleast as active as taxol and Taxotere.

In vivo, the products of general formula (I) in which Z represents aradical of general formula (II) were shown to be active in mice graftedwith B16 melanoma at doses of from 1 to 30 mg/kg administeredintraperitoneally, as well as on other liquid or solid tumours.

The new products have antitumour properties, and more especiallyactivity against tumours which are resistant to Taxol® or to Taxotere®.Such tumours comprise colon tumours which have a high expression of themdr 1 gene (multiple drug resistance gene). Multiple drug resistance isa customary term relating to the resistance of a tumour to differentproducts having different structures and mechanisms of action. Taxoidsare generally known to be strongly recognized by experimental tumourssuch as P388/DOX, a cell line selected for its resistance to doxorubicin(DOX) which expresses mdr 1.

The examples which follow illustrate the present invention.

EXAMPLE 1

126 mg of dicyclohexylcarbodiimide and then 14 mg of4-(N,N-dimethylamino)pyridine were added successively at a temperaturein the region of 20° C. to a suspension containing 217.8 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β,13α-dihydroxy-7β,10β-dimethoxy-9-oxo-11-taxene,200 mg of(2R,4S,5R)-3-tert-butoxycarbonyl-2-(4-methoxyphenyl)-4-phenyl-1,3-oxazolidine-5-carboxylicacid and 50 mg of powdered 4 Å molecular sieve in 2 cm³ of ethylacetate. The suspension obtained was stirred at a temperature in theregion of 20° C. under an argon atmosphere for 16 hours, and thenconcentrated to dryness under reduced pressure (0.27 kPa) at atemperature in the region of 40° C. The residue obtained was purified bychromatography at atmospheric pressure on 50 g of silica (0.063-0.2 mm)contained in a column 2 cm in diameter (elution gradient: ethylacetate/dichloromethane from 10:90 to 40:60 by volume), collecting10-cm³ fractions. Fractions containing only the desired product werepooled and concentrated to dryness under reduced pressure (0.27 kPa) at40° C. for 2 hours. 271.8 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β-hydroxy-7β,10β-dimethoxy-9-oxo-11-taxen-13α-yl(2R,4S,5R)-3-tert-butoxycarbonyl-2-(4-methoxyphenyl)-4-phenyl-1,3-oxazolidine-5-carboxylatewere thereby obtained in the form of a white solid, the characteristicsof which were as follows:

¹H NMR spectrum (400 MHz; CDCl₃ with a few drops of CD₃OD-d₄; chemicalshifts δ in ppm; coupling constants J in Hz): 1.02 (s, 9H: C(CH₃)₃);1.10 (s, 3H: CH₃); 1.17 (s, 3H: CH₃); 1.63 (s, 3H: CH₃); from 1.65 to1.85 and 2.60 (2 mts, 1H each; CH₂ at position 6); 1.78 (unres. comp.,3H: CH₃); 2.02 and 2.15 (2 dd, J=14 and 9, 1H each: CH₂ at position 14);2.14 (s, 3H: CH₃); 3.22 and 3.35 (2 s, 3H each: OCH₃); 3.64 (d, J=7, 1H:H at position 3); 3.73 (mt, 1H: H at position 7); 3.76 (s, 3H: ArOCH₃);4.06 and 4.16 (2 d, J=8.5, 1H each; CH₂ at position 20); 4.53 (d, J=5,1H: H at position 2′); 4.67 (s, 1H: H at position 10); 4.85 (broad d,J=10, 1H: H at position 5); 5.36 (mt, 1H: H at position 3′); 5.52 (d,J=7, 1H: H at position 2); 6.07 (mt, 1H: H at position 13); 6.33 (unres.comp., 1H: H at position 5′); 6.88 (d, J=8, 2H: aromatic H at the orthoposition with respect to OCH₃); from 7.25 to 7.40 (mt, 7H: aromatic H atposition 3′ and aromatic H at the meta position with respect to OCH₃);7.43 (t, J=7.5, 2H: OCOC₆H₅ H at the meta position); 7.58 (t, J=7.5, 1H:OCOC₆H₅ H at the para position); 7.96 (d, J=7.5, 2H: OCOC₆H₅ H at theortho position).

A solution of 446.3 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β-hydroxy-7β,10β-dimethoxy-9-oxo-11-taxen-13α-yl(2R,4S,5R)-3-tert-butoxycarbonyl-2-(4-methoxyphenyl)-4-phenyl-1,3-oxazolidine-5-carboxylatein 11.6 cm³ of a 0.1N solution of hydrogen chloride in ethanol wasstirred constantly at a temperature in the region of 0° C. for 16 hoursunder an argon atmosphere. The reaction mixture was then diluted with 40cm³ of dichloromethane and 5 cm³ of distilled water. After settling hadtaken place, the aqueous phase was separated and extracted with 5 cm³ ofdichloromethane. The organic phases were combined, dried over magnesiumsulphate, filtered through sintered glass and then concentrated todryness under reduced pressure (0.27 kPa) at a temperature in the regionof 40° C. 424.2 mg of a pale yellow solid were obtained, which productwas purified by preparative thin-layer chromatography [12 Merckpreparative silica gel 60F₂₅₄ plates, thickness 1 mm, application insolution in a methanol/dichloromethane (5.95 by volume) mixture, elutingwith a methanol/dichloromethane (5:95 by volume) mixture]. After elutionof the zone corresponding to the main product with amethanol/dichloromethane (15:85 by volume) mixture, filtration throughsintered glass and evaporation of the solvents under reduced pressure(0.27 kPa) at a temperature in the region of 40° C., 126 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β-hydroxy-7β,10β-dimethoxy-9-oxo-11-taxen-13α-yl(2R,3S)-3-tert-butoxycarbonylamino-2-hydroxy-3-phenylpropionate wereobtained in the form of an ivory-coloured foam, the characteristics ofwhich were as follows:

optical rotation [α]₂₀ ^(D)=−32.9 (c=0.5; methanol)

¹H NMR spectrum (400 MHz, CDCl₃; chemical shifts δ in ppm; couplingconstants J in Hz): 1.23 (s, 3H: CH₃); 1.25 (s, 3H: CH₃); 1.39 (s, 9H:C(CH₃)₃); 1.70 (s, 1H: OH at position 1); 1.75 (s, 3H: CH₃); 1.82 and2.72 (2 mts, 1H each: CH₂ at position 6); 1.91 (s, 3H: CH₃); 2.31(limiting AB, 2H: CH₂ at position 14); 2.39 (s, 3H: COCH₃); 3.33 and3.48 (2 s, 3H each: OCH₃); 3.48 (mt, 1H: OH at position 2′); 3.85 (d,J=7, 1H: H 3); 3.88 (dd, J=11 and 7, 1H: H 7); 4.20 and 4.33 (2 d,J=8.5, 1H each: CH₂ at position 20); 4.65 (mt, 1H: H at position 2′);4.83 (s, 1H: H at position 10); 5.00 (broad d, J=10, 1H: H at position5); 5.30 (broad d, J=10, 1H: H at position 3′); 5.47 (d, J=10, 1H:CONH); 5.66 (d, J=7, 1H: H at position 2); 6.24 (broad t, J=9, 1H: H atposition 13); from 7.30 to 7.50 (mt, 5H: aromatic H at position 3′);7.52 (t, J=7.5, 2H: OCOC₆H₅ H at the meta position); 7.63 (t, J=7.5, 1H:OCOC₆H₅ H at the para position); 8.12 (d, J=7.5, 2H: OCOC₆H₅ H at theortho position).

4α-Acetoxy-2α-benzoyloxy-5β,20-epoxy-1β,13α-dihydroxy-7β,10β-dimethoxy-9-oxo-11-taxene(or 7β,10β-dimethoxy-10-deacetoxybaccatin III) was prepared in thefollowing manner:

86 mg of sodium hydride at a concentration of 50% by weight in liquidparaffin were added portionwise to a solution, maintained under an argonatmosphere, at a temperature in the region of 0° C., of 500 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β,7β,13α-trihydroxy-10β-methoxy-9-oxo-11-taxenein 5 cm³ of iodomethane and 0.5 cm³ of dimethylformamide. After 45minutes at a temperature in the region of 0° C., the reaction mixturewas diluted with 50 cm³ of ethyl acetate and 8 cm³ of distilled water.After settling had taken place, the organic phase was separated andwashed with twice 8 cm³ of distilled water and then 8 cm³ of saturatedaqueous sodium chloride solution, dried over magnesium sulphate,filtered through sintered glass and concentrated to dryness underreduced pressure (0.27 kPa) at a temperature in the region of 40° C. 570mg of a pale yellow solid were thereby obtained, which product waspurified by chromatography at atmospheric pressure on 50 g of silica(0.063-0.2 mm) contained in a column 2.5 cm in diameter, eluting with amethanol/dichloromethane (2:98 by volume) mixture and collecting 10-cm³fractions. Fractions containing only the desired product were pooled andconcentrated to dryness under reduced pressure (0.27 kPa) at 40° C. for2 hours. 380 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β,13α-dihydroxy-7β,10β-dimethoxy-9-oxo-11-taxenewere thereby obtained in the form of a pale yellow solid, thecharacteristics of which were as follows:

¹H NMR spectrum (400 MHz; CDCl₃; with a few drops of CD₃OD-d₄; chemicalshifts δ in ppm; coupling constants J in Hz): 1.03 (s, 3H: CH₃); 1.11(s, 3H: CH₃); 1.65 (s, 3H: CH₃); 1.72 and 2.67 (2 mts, 1H each: CH₂ atposition 6); 2.05 (s, 3H: CH₃): 2.21 (limiting AB, J=14 and 9, 2H: CH₂at position 14); 2.25 (s, 3H: COCH₃); 3.26 and 3.40 (2 s, 3H each:OCH₃); 3.85 (d, J=7, 1H: H at position 3); 3.89 (dd, J=11 and 6.5, 1H: Hat position 7); 4.12 and 4.25 (2 d, J=8.5, 1H each: CH₂ at position 20);4.78 (broad t, J=9, 1H: H at position 13); 4.83 (s, 1H: H at position10); 4.98 (broad d, J=10, 1H: H at position 5); 5.53 (d, J=7, 1H: H atposition 2); 7.43 (t, J=7.5, 2H: OCOC₆H₅ H at the meta position); 7.56(t, J=7.5, 1H: OCOC₆H₅ H at the para position); 8.05 (d, J=7.5, 2H:OCOC₆H₅ H at the ortho position).

4α-Acetoxy-2α-benzoyloxy-5β,20-epoxy-1β,7β,13α-trihydroxy-10β-methoxy-9-oxo-11-taxene(or 10β-methoxy-10-deacetoxybaccatin III) was prepared in the followingmanner:

50 cm³ of hydrogen fluoride/triethylamine complex (3HF.Et₃N) were addedslowly to a solution, maintained under an argon atmosphere, at atemperature in the region of 0° C., of 3.62 g of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β-hydroxy-10β-methoxy-9-oxo-7β,13α-bis(triethylsilyoxy)-11-taxenein 30 cm³ of dichloromethane. After 48 hours at a temperature in theregion of 20° C., the reaction mixture was poured into a suspension of100 cm³ of supersaturated aqueous sodium hydrogen carbonate solutionmaintained at a temperature in the region of 0° C. After settling hadtaken place, the aqueous phase was separated and re-extracted with threetimes 80 cm³ of dichloromethane and then twice 80 cm³ of ethyl acetate.The organic phases were combined, dried over magnesium sulphate,filtered through magnesium sulphate and concentrated to dryness underreduced pressure (0.27 kPa) at a temperature in the region of 40° C.3.45 g of a yellow foam were thereby obtained, which product waspurified by chromatography at atmospheric pressure on 150 g of silica(0.063-0.2 mm) contained in a column 3.5 cm in diameter, eluting with amethanol/dichloromethane (5:95 by volume) mixture and collecting 35-cm³fractions. Fractions containing only the desired product were pooled andconcentrated to dryness under reduced pressure (0.27 kPa) at 40° C. for2 hours. 1.97 g of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β,7β,13α-trihydroxy-10β-methoxy-9-oxo-11-taxenewere thereby obtained in the form of a white solid, the characteristicsof which were as follows:

¹H NMR spectrum (400 MHz; CDCl₃; chemical shifts δ in ppm; couplingconstants J in Hz): 1.10 (s, 3H: CH₃); 1.19 (s, 3H: CH₃); 1.48 (d,J=8.5, 1H: OH at position 13); 1.70 (s, 3H: CH₃); 1.81 and 2.61 (2 mts,1H each: CH₂ at position 6); 2.09 (d, J=5, 1H: OH at position 7); 2.11(s, 3H: CH₃); 2.30 (s, 3H: COCH₃); 2.32 (d, J=9, 2H: CH₂ at position14); 3.48 (s, 3H: OCH₃); 3.97 (d, J=7, 1H: H at position 3); 4.18 and4.33 (2 d, J=8.5, 1H each: CH₂ at position 20); 4.31 (mt, 1H: H atposition 7); 4.93 (mt, 1H: H at position 13); 4.99 (s, 1H: H at position10); 5.01 (broad d, J=10, 1H: H at position 5); 5.66 (d, J=7, 1H: H atposition 2); 7.49 (t, J=7.5, 2H: OCOC₆H₅ H at the meta position); 7.63(t, J=7.5, 1H: OCOC₆H₅ H at the para position); 8.12 (d, J=7.5, 2H:OCOC₆H₅ H at the ortho position).

4α-Acetoxy-2α-benzoyloxy-5β,20-epoxy-1β-hydroxy-10β-methoxy-9-oxo-7β,13α-bis(triethylsilyloxy)-11-taxene(or 10β-methoxy-10-deacetoxy-7,13-bis(triethylsilyl)baccatin III) wasprepared in the following manner:

375 mg of sodium hydride at a concentration of 50% by weight in liquidparaffin were added portionwise to a solution, maintained under an argonatmosphere, at a temperature in the region of 0° C., of 5 g of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β,10β-dihydroxy-9-oxo-7β,13α-bis(triethylsilyloxy)-11-taxenein 25 cm³ of iodomethane. The solution was stirred constantly for 45minutes at a temperature in the region of 0° C., and then for 5 hours 30minutes at a temperature in the region of 20° C. The reaction mixturewas cooled again to a temperature in the region of 0° C., and 125 mg ofsodium hydride at a concentration of 50% by weight in liquid paraffinwere added portionwise. After 1 hour at 20° C. and then 18 hours at 5°C., the reaction mixture was diluted by adding 50 cm³ of dichloromethaneand poured into 50 cm³ of saturated aqueous ammonium chloride solution,and settling was allowed to take place. The aqueous phase was separatedand extracted with twice 30 cm³ of dichloroemethane, and the organicphases were then combined, washed with 10 cm³ of distilled water, driedover magnesium sulphate, filtered through sintered glass andconcentrated to dryness under reduced pressure (0.27 kPa) at atemperature in the region of 40° C. 5.15 g of a yellow foam were therebyobtained, which product was purified by chromatography at atmosphericpressure on 300 g of silica (0.063-0.2 mm) contained in a column 5 cm indiameter (elution gradient: ethyl acetate/dichloromethane from 0:100 to10:90 by volume), collecting 30-cm³ fractions. Fractions containing onlythe desired product were pooled and concentrated to dryness underreduced pressure (0.27 kPa) at 40° C. for 2 hours. 3.62 g of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β-hydroxy-10β-methoxy-9-oxo-7β,13α-bis(triethylsilyloxy)-11-taxenewere thereby obtained in the form of a pale yellow foam, thecharacteristics of which were as follows:

¹H NMR spectrum (600 MHz; CDCl₃; chemical shifts δ in ppm; couplingconstants J in Hz): 0.58 and 0.69 (2 mts, 6H each: ethyl CH₂); 0.97 and1.04 (2 t, J=7.5, 9H each: ethyl CH₃); 1.15 (s, 3H: CH₃); 1.18 (s, 3H:CH₃); 1.58 (s, 1H: OH at position 1); 1.68 (s, 3H: CH₃); 1.89 and 2.48(2 mts, 1H each: CH₂ at position 6); 2.04 (s, 3H: CH₃); 2.15 and 2.23 (2dd, J=16 and 9, 1H each: CH₂ at position 14); 2.29 (s, 3H: COCH₃); 3.40(s, 3H: OCH₃); 3.83 (d, J=7, 1H: H at position 13); 4.15 and 4.30 (2 d,J=8.5, 1H each: CH₂ at position 20); 4.43 (dd, J=11 and 7, 1H: H atposition 7); 4.91 (s, 1H: H at position 10); 4.96 (broad d, J=10, 1H atposition 5); 5.01 (broad t, J=9, 1H: H at position 13); 5.62 (d, J=7,1H: H at position 2); 7.46 (t, J=7.5, 2H: OCOC₆H₅ H at the metaposition); 7.60 (t, J=7.5, 1H: OCOC₆H₅ H at the para position); 8.09 (d,J=7.5, 2H: OCOC₆H₅ H at the ortho position).

4α-Acetoxy-2α-benzoyloxy-5β,20-epoxy-1β,10β-dihydroxy-9-oxo-7β,13α-bis(triethylsilyloxy)-11-taxene(or 10-deacetyl-7,13-bis(triethylsilyl)baccatin III) was prepared in thefollowing manner:

10.8 cm³ of triethylsilyl chloride were added to a solution, maintainedunder an argon atmosphere, at a temperature in the region of 20° C., of14 g of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β,7β,10β,13α-tetrahydroxy-9-oxo-11-taxene(10-deacetylbaccatin III) in 50 cm³ of anhydrous pyridine. After 17hours at a temperature in the region of 20° C., the reaction mixture wasbrought to a temperature in the region of 115° C. and 10.8 cm³ oftriethylsilyl chloride were then added. After 3 hours 15 minutes at atemperature in the region of 115° C., the reaction mixture was broughtback to a temperature in the region of 20° C. and diluted with 30 cm³ ofethyl acetate and 100 cm³ of distilled water. After settling took place,the aqueous phase was separated and extracted with twice 50 cm³ of ethylacetate. The organic phases were combined, washed with 50 cm³ ofsaturated aqueous sodium chloride solution, dried over magnesiumsulphate, filtered through sintered glass and then concentrated todryness under reduced pressure (0.27 kPa) at a temperature in the regionof 40° C. 63.1 g of a brown oil were thereby obtained, which product waspurified by chromatography at atmospheric pressure on 800 g of silica(0.063-0.2 mm) contained in a column 7 cm in diameter (elution gradient:ethyl acetate/dichloromethane from 0.100 to 5.95 by volume), collecting60-cm³ fractions. Fractions containing only the desired product werepooled and concentrated to dryness under reduced pressure (0.27 kPa) at40° C. for 2 hours. 9.77 g of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β,10β-dihydroxy-9-oxo-7β,13α-bis(triethylsilyloxy)-11-taxenewere thereby obtained in the form of a cream-coloured foam, thecharacteristics of which were as follows:

¹H NMR spectrum (400 MHz; CDCl₃, chemical shifts δ in ppm; couplingconstants J in Hz): 0.55 and 0.68 (2 mts, 6H each: ethyl CH₂); 0.94 and1.03 (2 t, J=9.5, 9H each: ethyl CH₃); 1.08 (s, 3H: CH₃); 1.17 (s, 3H:CH₃); 1.58 (s, 1H: OH at position 1); 1.73 (s, 3H: CH₃); 1.91 and 2.57(2 mts, 1H each: CH₂ at position 2); 2.04 (s, 3H: CH₃); 2.12 and 2.23 (2dd, J=16 and 9, 1H each: CH₂ at position 14); 2.30 (s, 3H: COCH₃); 3.88(d, J=7, 1H: H at position 3); 4.16 and 4.32 (2 d, J=8.5, 1H each: CH₂position 20); 4.27 (d, J=1, 1H: OH at position 10); 4.40 (dd, J=11 and7, 1H: H at position 7); 4.95 (broad d, J=10, 1H: H at position 5); 4.95(mt, 1H: H at position 13): 5.16 (d, J=1, 1H: H at position 10); 5.60(d, J=7, 1H: H at position 2); 7.46 (t, J=7.5, 2H: OCOC₆H₅ H at the metaposition); 7.60 (t, J=7.5, 1H: OCOC₆H₅ H at the para position); 8.09 (d,J=7.5, 2H: OCOC₆H₅ H at the ortho position).

EXAMPLE 2

340 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β-hydroxy-7β,10β-dimethoxy-9oxo-11-taxen-13α-yl(2R, 4S,5R)-3-tert-butoxycarbonyl-2-(4-methoxyphenyl)-4-phenyl-1,3-oxazolidine-5-carboxylatewere dissolved in 8 cm³ of a 0.1N ethanolic solution of hydrochloricacid containing 1% of water. The solution thereby obtained was stirredfor 13 hours at a temperature in the region of 20° C. and then for 80hours at 4° C., and 20 cm³ of dichloromethane were added. The organicphase was separated after settling had taken place and washedsuccessively with 3 times 5 cm³ of saturated aqueous sodium hydrogencarbonate solution, dried over magnesium sulphate, filtered andconcentrated to dryness under reduced pressure (2.7 kPa) at 40° C. 300mg of a while foam were obtained, which product was purified bychromatography on silica gel deposited on plates [gel 1 mm thick, plates20×20 cm, eluent: dichloromethane/methanol (95.5 by volume)] in 80-mgfractions (4 plates). After localization with UV rays of the zonecorresponding to the adsorbed desired product, this zone was scrapedoff, and the silica collected was washed on sintered glass with 10 times5 cm³ of ethyl acetate. The filtrates were combined and concentrated todryness under reduced pressure (2.7 kPa) at 40° C. A white foam wasobtained, which was repurified according to the same technique [3plates: 20×20×1 mm; eluent: dichloromethane/ethyl acetate (90:10 byvolume)]. 205 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β-hydroxy-7β,10β-dimethoxy-9-oxo-11-taken-13α-yl(2R, 3S)-3-tert-butoxycarbonylamino-2-hydroxy-3-phenylpropionate werethereby obtained in the form of a white foam, the characteristics ofwhich were as follows:

optical rotation [α]_(D) ²⁰=−33 (c=0.5; methanol).

¹H NMR spectrum (400 MHz; CDCl₃; chemical shifts δ in ppm; couplingconstants J in Hz): 1.23 (s, 3H: —CH₃); 1.25 (s, 3H: —CH₃); 1.39 [s, 9H:—C(CH₃)₃]; 1.70 , (s, 1H; —OH at position 1); 1.75 (s, 3H: —CH₃); 1.82and 2.72 (2 mts, 1H each: —CH₂ at position 6); 1.91 (s, 3H: —CH₃); 2.31(limiting AB, 2H: —CH₂ at position 14); 2.39 (s, 3H: —COCH₃); 3.33 and3.48 (2 s, 3H each: —OCH₃); 3.46 (mt, 1H: OH at position 2′); 3.85 (d,J=7, 1H: —H at position 3); 3.88 (dd, J=11 and 7, 1H at position 7);4.20 and 4.33 (2 d, J=8.5, 1H each: —CH₂ at position 20); 4.65 (mt, 1H:—H at position 2′); 4.83 (s, 1H: —H at position 10); 5.00 (broad d,J=10, 1H: —H at position 5); 5.30 (broad d, J=10, 1H: —H at position3′); 5.47 (d, J=10, 1H: —CONH—); 5.66 (d, J=7, 1H: —H at position 2);6.24 (broad t, J=9, 1H: —H at position 13); from 7.30 to 7.50 (mt, 5H:—C₆H₅ at position 3′); 7.52 [t, J=7.5, 2H: —OCOC₆H₅ (—H at position 3and H at position 5)]; 7.63 [t, J=7.5, 1H: —OCOC₆H₅ (—H at position 4)];8.12 [d, J=7.5, 2H: —OCOC₆H₅ (—H at position 2 and H at position 6)].

4α-Acetoxy-2α-benzoyloxy-5β,20-epoxy-1β-hydroxy-7β,10β-dimethoxy-9-oxo-11-taxen-13α-yl(2R, 4S,5R)-3-tert-butoxycarbonyl-2-(4-methoxyphenyl)-4-phenyl-1,3-oxazolidine-5-carboxylatewas prepared in the following manner:

100 cm³ of an ethanolic suspension of activated nickel according toRaney (obtained from 80 cm³ of the approximately 50% commercial aqueoussuspension by successive washing, to a pH in the region of 7, with 15times 100 cm³ of distilled water and with 5 times 100 cm³ of ethanol)were added at a temperature in the region of 20° C. to a solution,maintained under an argon atmosphere and kept stirring, of 1 g of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β-hydroxy-7β,10β-bis(methylthiomethoxy)-9-oxo-11-taxen-13α-yl(2R, 4S,5R)-3-tert-butoxycarbonyl-2-(4-methoxyphenyl)-4-phenyl-1,3-oxazolidine-5-carboxylatein 100 cm³ of anhydrous ethanol. The reaction medium was kept stirringfor 24 hours at a temperature in the region of 20° C. and then filteredthrough sintered glass. The sintered glass was washed with 4 times 80cm³ of ethanol, and the filtrates were combined and concentrated todryness under reduced pressure (2.7 kPa) at 40° C. 710 mg of a yellowfoam were obtained, which product was purified by chromatography on 60 gof silica (0.063-0.2 mm) contained in a column 2.5 cm in diameter[eluent: dichloromethane/ethyl acetate (90:10 by volume)], collecting6-cm³ fractions. Fractions containing only the desired product arepooled and concentrated to dryness under reduced pressure (2.7 kPa) at40° C. 350 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β-hydroxy-7β,10β-dimethoxy-9-oxo-11-taxen-13α-yl(2R, 4S,5R)-3-tert-butoxycarbonyl-2-(4-methoxyphenyl)-4-phenyl-1,3-oxazolidine-5-carboxylatewere thereby obtained in the form of a white foam.

4α-Acetoxy-2α-benzoyloxy-5β,20-epoxy-1β-hydroxy-7β,10β-bis(methylthiomethoxy)-9-oxo-11-taxen-13α-yl(2R, 4S,5R)-3-tert-butoxycarbonyl-2-(4-methoxy-phenyl)-4-phenyl-1,3-oxazolidine-5-carboxylatewas prepared in the following manner:

2.3 cm³ of acetic acid and 7.55 cm³ of acetic anhydride were added at atemperature in the region of 20° C. to a solution, maintained under anargon atmosphere and kept stirring, of 3.1 g of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β-7β,10β-trihydroxy-9-oxo-11-taxen-13α-yl (2R, 4S,5R)-3-tert-butoxycarbonyl-2-(4-methoxyphenyl)-4-phenyl-1,3-oxazolidine-5-carboxylatedissolved in 102 cm³ of dimethyl sulphoxide. The reaction mixture waskept stirring for 7 days at a temperature in the region of 20° C., andthen poured into a mixture of 500 cm³ of distilled water and 250 cm³ ofdichloromethane. 30 cm³ of saturated aqueous potassium carbonatesolution was then added with efficient stirring to a pH in the region of7. After 10 minutes of stirring, the organic phase was separated aftersettling had taken place and the aqueous phase was re-extracted withtwice 250 cm³ of dichloromethane. The organic phases were combined,washed with 250 cm³ of distilled water, drive over magnesium sulphate,filtered and concentrated to dryness under reduced pressure (2.7 kPa) at40° C. 5.2 g of a pale yellow oil were obtained, which product waspurified by chromatography on 200 g of silica (0.063-0.4 mm) containedin a column 3 cm in diameter [eluent: dichloromethane/methanol (99:1 byvolume)], collecting 50-cm³ fractions. Fractions containing only thedesired product were pooled and concentrated to dryness under reducedpressure (2.7 kPa) at 40° C. 1.25 g of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β-hydroxy-7β,10β-bis(methylthiomethoxy)-9-oxo-11-taxen-13α-yl(2R, 4S,5R)-3-tert-butoxycarbonyl-2-(4-methoxyphenyl)-4-phenyl-1,3-oxazolidine-5-carboxylatewere thereby obtained in the form of a white foam.

4α-Acetoxy-2α-benzoyloxy-5β,20-epoxy-1β,7β,10β-trihydroxy-9-oxo-11-taxen-13α-yl(2R, 4S,5R)-3-tert-butoxycarbonyl-2-(4-methoxyphenyl)-4-phenyl-1,3-oxazolidine-5-carboxylatewas prepared in the following manner.

A solution of 5.1 g of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β-hydroxy-9-oxo-7β,10β-bis(2,2,2-trichloroethoxycarbonyloxy)-11-taxen-13α-yl(2R, 4S,5R)-3-tert-butoxycarbonyl-2-(4-methoxyphenyl)-4-phenyl-1,3-oxazolidine-5-carboxylatein a mixture of 100 cm³ of methanol and 100 cm³ of acetic acid washeated, with stirring and under an argon atmosphere, to a temperature inthe region of 60° C., and 10 g of powdered zinc were then added. Thereaction mixture was then stirred for 15 minutes at 60° C., thereaftercooled to a temperature in the region of 20° C. and filtered throughsintered glass lined with Celite. The sintered glass was washed withtwice 15 cm³ of methanol. The filtrate was concentrated to dryness underreduced pressure (2.7 kPa) at a temperature in the region of 40° C. 50cm³ of ethyl acetate and 25 cm³ of saturated aqueous sodium hydrogencarbonate solution were added to the residue. The organic phase wasseparated after settling had taken place and washed successively with 25cm³ of saturated aqueous sodium hydrogen carbonate solution and with 25cm³ of distilled water, then dried over magnesium sulphate, filteredthrough sintered glass and concentrated to dryness under reducedpressure (2.7 kPa) at 40° C. 3.1 g of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β,7β,10β-trihydroxy-9-oxo-11taxen-13α-yl (2R, 4S,5R)-3-tert-butoxycarbonyl-2-(4-methoxyphenyl)-4-phenyl-1,3-oxazolidine-5-carboxylatewere thereby obtained in the form of a white foam.

4α-Acetoxy-2α-benzoyloxy-5β,20-epoxy-1β-hydroxy-9-oxo-7β,10β-bis(2,2,2-trichloroethoxy-carbonyloxy)-11-taxen-13α-yl(2R, 4S,5R)-3-tert-butoxy-carbonyl-2-(4-methoxyphenyl)-4-phenyl-1,3-oxazolidine-5-carboxylatewas prepared under the conditions described in Patent WO 94/07878, thedisclosure of which is specifically incorporated by reference herein.

EXAMPLE 3

76 mg of dicyclohexylcarbodiimide and then 8.5 mg of4-(N,N-dimethylamino)pyridine were added successively at a temperaturein the region of 20° C. to a suspension containing 135 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-10β-ethoxy-1β,13α-dihydroxy-7β-methoxy-9-oxo-11-taxene,120 mg of (2R, 4S,5R)-3-tert-butoxycarbonyl-2-(4-methoxyphenyl)-4-phenyl-1,3-oxazolidine-5-carboxylicacid and 50 mg of powdered 4 Å molecular sieve in 1 cm³ of anhydroustoluene. The suspension obtained was stirred at a temperature in theregion of 20° C. under an argon atmosphere for 1 hour, and then purifiedby direct application to a column for chromatography at atmosphericpressure on 30 g of silica (0.063-0.2 mm) contained in a column 2.5 cmin diameter (elution gradient: ethyl acetate/dichloromethane from 2.98to 10:90 by volume), collecting 10-cm³ fractions. Fractions containingonly the desired product were pooled and concentrated to dryness underreduced pressure (2.7 kPa) at 40° C. for 2 hours. 320.6 mg of a whitesolid were thereby obtained, which product was purified by preparativethin-layer chromatography: 10 Merck preparative silica gel 60F₂₅₄plates, thickness 0.5 mm, application in solution in dichloromethane,eluting with a methanol/dichloromethane (3.97 by volume) mixture. Afterelution of the zones corresponding to the main products with amethanol/dichloromethane (15.85 by volume) mixture, filtration throughcotton wool and then evaporation of the solvents under reduced pressure(2.7 kPa) at a temperature in the region of 40° C., 47.7 mg of4α-acetoxy-2α-benzoyloxy-5β,20epoxy-10β-ethoxy-1β,13α-dihydroxy-7β-methoxy-9-oxo-11-taxenewere obtained in the form of a cream-coloured solid and 37 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-10β-ethoxy-1β-hydroxy-7β-methoxy-9-oxo-11-taxen-13α-yl(2R, 4S,5R)-3-tert-butoxycarbonyl-2-(4-methoxyphenyl)-4-phenyl-1,3-oxazolidine-5-carboxylatewere obtained in the form of a white foam, the characteristics of which5-carboxylate product were as follows:

¹H NMR spectrum (600 MHz; CDCl₃; at a temperature of 333 K; chemicalshifts δ in ppm; coupling constants J in Hz): 1.09 (s, 9H: C(CH₃)₃; 1.19(s, 3H: CH₃); 1.27 (t, J=7, 3H: ethyl CH₃); 1.43 (s, 1H; OH at position1); 1.62 (s, 3H: CH₃); 1.68 (s, 3H: CH₃); 1.77 and 2.63 (2 mts, 1H each:CH₂ at position 6); 1.86 (s, 3H: COCH₃); 2.13 and 2.22 (2 dd, J=16 and9, 1H each: CH₂ at position 14); 3.27 (s, 3H: OCH₃); 3.45 and 3.68 (2mts. 1H each: ethyl CH₂); 3.76 (d, J=7, 1H: H3); 3.81 (s, 3H: ArOCH₃);3.85 (dd, J=11 and 7, 1H: H at position 7); 4.13 and 4.23 (2 d, J=8.5,1H each: CH₂ at position 20); 4.58 (d, J=4.5, 1H: H at position 2′);4.83 (s, 1H: H at position 10); 4.90 (broad d, J=10, 1H: H at position5); 5.46 (d, J=4.5, 1H: H at position 3′); 5.60 (d, J=7 Hz, 1H: H2);6.13 (broad t, J=9 Hz, 1H: H13); 6.38 (s, 1H: H5′); 6.92 (d, J=8.5, 2H:aromatic H at the ortho position with respect to OCH₃); from 7.30 to7.50 (mt, 9H: aromatic H at position 3′-aromatic H at the meta positionwith respect of OCH₃ and OCOC₆H₅ H at the meta position); 7.59 (t,J=7.5, 1H: OCOC₆H₅ H at the para position); 8.03 (d, J=7.5, 2H: OCOC₆H₅H at the ortho position).

A solution of 48 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-10β-ethoxy-1β-hydroxy-7β-methoxy-9-oxo-11-taxen-13α-yl(2R, 4S,5R)-3-tert-butoxycarbonyl-2-(4-methoxyphenyl)-4-phenyl-1,3-oxazolidine-5-carboxylatein 0.5 cm³ of ethyl acetate and 0.004 cm³ of concentrated 37%hydrochloric acid was kept stirring at a temperature in the region of20° C. for 1.5 hours under an agon atmosphere. The reaction mixture wasthen purified by preparative thin-layer chromatography; application ofthe crude reaction mixture to 5 Merck preparative silica gel 60F₂₅₄plates, thickness 0.5 mm, eluting with a methanol/dichloromethane (4:96by volume) mixture. After elution of the zone corresponding to the mainproduct with a methanol/dichloromethane (15:85 by volume) mixture,filtration through cotton wool and then evaporation of the solventsunder reduced pressure (2.7 kPa) at a temperature in the region of 40°C., 28.5 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-10β-ethoxy-1β-hydroxy-7β-methoxy-9-oxo-11-taxen-13α-yl(2R, 3S)-3-tert-butoxycarbonylamino-2-hydroxy-3-phenylpropionate wereobtained in the form of an ivory-coloured foam, the characteristics ofwhich were as follows:

¹H NMR spectrum (400 MHz; CDCl₃; chemical shifts δ in ppm; couplingconstants J in Hz): 1.22 (s, 3H: CH₃); 1.25 (s, 3H: CH₃); 1.32 (t, J=7,3H: ethyl CH₃); 1.38 (s, 9H: C(CH₃)₃; 1.64 (s, 1H: OH at position 1);1.73 (s, 3H: CH₃); 1.80 and 2.70 (2 mts, 1H each: CH₂ at position 6);1.88 (s, 3H: CH₃); 2.30 (mt, 2H: CH₂ at position 14); 2.38 (s, 3H,COCH₃); 3.31 (s, 3H: OCH₃); 3.44 (unres. comp. 1H: OH at position 2′);3.50 and 3.70 (2 mts, 1H, each: ethyl OCH₂); 3.84 (d, J=7.5, 1H: H atposition 3); 3.87 (dd, J=11 and 6.5, 1H: H at position 7); 4.18 and 4.32(2 d, J =8.5, 1H each: CH₂ at position 20); 4.64 (mt, 1H: H at position2¹); 4.90 (s, 1H: H at position 10); 4.98 (broad, d, J=10, 1H: H atposition 5); 5.28 (broad, d, J=10, 1H: H at position 3′); 5.42 (d, J=10,1H: CONH); 5.64 (d, J=7.5, 1H: H at position 2); 6.22 (broad, t, J=9,1H: H at position 13); from 7.25 to 7.45 (mt, 5H: aromatic H at position3′); 7.50 (d, J=7.5, 2H: OCOC₆H₅ H at the meta position); 7.62 (t,J=7.5, 1H: OCOC₆H₅ H at the para position); 8.12 (d, J=7.5, 2H: OCOC₆H₅H at the ortho position).

4α-Acetoxy-2α-benzoyloxy-5β,20-epoxy-10β-ethoxy-1β,13α-dihydroxy-7β-methoxy-9-oxo-11-taxene(or 10β-ethoxy-7β-methoxy-10-deacetoxybaccatin III) may be prepared inthe following manner:

43 mg sodium hydride at a concentration of 50% by weight in liquidparaffin were added portionwise to a solution, maintained under an argonatmosphere, at a temperature in the region of 0° C., of 235 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β,7β,13α-trihydroxy-10β-ethoxy-9-oxo-11-taxene-2.5cm³ of iodomethane and 1 cm³ of dimethylformamide. After 30 minutes at atemperature in the region of 0° C., the reaction mixture was dilutedwith 40 cm³ of ethyl acetate, 6 cm³ of distilled water and 8 cm³ ofsaturated aqueous ammonium chloride solution. After setting had takenplace, the organic phase was separated and washed with three times 8 cm³of distilled water and then 8 cm³ of saturated aqueous NaCl solution,dried over magnesium sulphate, filtered through sintered glass andconcentrated to dryness under reduced pressure (2.7 kPa) at atemperature in the region of 40° C. 268 mg of a yellow solid werethereby obtained, which product was purified by chromatography atatmospheric pressure on 30 g of silica (0.063-0.2 mm) contained in acolumn 2.5 cm in diameter (elution gradient: ethylacetate/dichloromethane from 0:100 to 15.85 by volume), collecting10-cm³ fractions. Fractions containing only the desired product werepooled and concentrated to dryness under reduced pressure (0.27 kPa) at40° C. for 2 hours. 380 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-10β-ethoxy-1β,13α-dihydroxy-7β-methoxy-9-oxo-11-taxeneare thereby obtained in the form of a white powder, the characteristicof which were as follows:

¹H NMR spectrum (300 MHz; CDCl₃ with the addition of a few drops ofCD₃OD-d₄; chemical shifts δ in ppm, coupling constants J in Hz): 0.99(s, 3H: CH₃); 1.09 (s, 3H; CH₃); 1.22 (t, J=7, 3H: ethyl CH₃); 1.62 (s,3H: CH₃); 1.68 and 2.66 (2 mts, 1H each: CH₂6); 2.03 (s, 3H, CH₃); 2.13and 2.22 (2 dd, J =16 and 9, 1H each: CH₂ at position 14); 2.23 (s, 3H:COCH₃); 3.23 (s, 3H: OCH₃); from 3.40 to 3.65 (mt, 2H; ethyl CH₂); 3.84(d, J=7.5, 1H: H at position 3); 3.88 (dd, J=10 and 6.5, 1H: H atposition 7); 4.10 and 4.23 (2 d, J=8.5, 1H each: CH₂20); 4.75 (broad t,J=9, 1H: H at position 13); 4.90 (s, 1H: H at position 10); 4.97 (broadd, J=10, 1H: H at position 5); 5.51 (d, J=7.5, 1H: H at position 2);7.42 (t, J=7.5, 2H: OCOC₆H₅ H at the meta position); 7.53 (t, J=7.5, 1H:OCOC₆H₅ at the para position); 8.03 (d, J=7.5, 2H: OCOC₆H₅ H at theortho position).

4α-Acetoxy-2α-benzoyloxy-5β,20-epoxy-1β,7β,13α-trihydroxy-10β-ethoxy-9-oxo-11-taxene(or 10β-ethoxy-10-deacetoxybaccatin III) was prepared in the followingmanner:

9 cm³ of hydrogen fluoride/triethylamine (3HF.ET₃N) were added to asolution, maintained under an argon atmosphere, at a temperature in theregion of 20° C., of 591 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β,hydroxy-10β-ethoxy-9-oxo-7β,13α-bis(triethylsilyloxy)-11-taxene in 6 cm³ of dichloromethane. After 21 hoursat a temperature in the region of 20° C., the reaction mixture wasdiluted with 40 cm³ of dichloromethane and poured into a suspension of40 cm³ of supersaturated aqueous sodium hydrogen carbonate solutionmaintained at a temperature in the region of 0° C. After dilution with10 cm³ distilled water and when setting had taken place, the aqueousphase was separated and re-extracted with twice 20 cm³ of diethyl ether.The organic phases were combined, washed with 20 cm³ of distilled waterand 20 cm³ of saturated aqueous sodium chloride solution, dried overmagnesium sulphate, filtered through magnesium sulphate and concentratedto dryness under reduced pressure (2.7 kPa) at a temperature in theregion of 40° C. 370 mg of a pale yellow foam were thereby obtained,which product is purified by chromatography at atmospheric pressure on35 g of silica (0.0632-0.2 mm) contained in a column 2.5 cm in diameter,elutin with a methanol/dichloromethane (2:98 by volume) mixture andcollecting 15-cm³ fractions. Fractions containing only the desiredproduct were pooled and concentration to dryness under reduced pressure(2.7 kPa) at 40° C. for 2 hours. 236.2 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β,7β,13α-trihydroxy-10β-ethoxy-9-oxo-11-taxenewere thereby obtained in the form of a white solid, the characteristicsof which were as follows:

¹H NMR spectrum (400 MHz; CDCl₃: chemical shifts δ in ppm, couplingconstants J in Hz): 1.08 (s, 3H: CH₃); 1.19 (s, 3H: CH₃); 1.29 (t,J=7.5, 3H: ethyl CH₃); 1.38 (d, J=9, 1H: OH at position 7); 1.59 (s, 1H:OH at position 1); 1.69 (s, 3H: CH₃); 1.82 and 2.62 (2 mts, 1H each: CH₂at position 6); 2.02 (d, J=5, 1H: OH at position 13); 2.08 (s, 3H: CH₃);2.30 (s, 3H: COCH₃); 2.32 (d, J=9, 2H: CH₂ at position 14); 3.56 and3.67 (2 mts, 1H each: ethyl OCH₂); 3.98 (d, J=7, 1H: H at position 3);4.18 and 4.33 (2 d, J=8.5 Hz, 1H each: CH₂20); 4.30 (mt, 1H: H7); 4.90(mt, 1H: H at position 13); 4.99 (dd, J=10 and 1.5, 1H: at position 5);5.05 (s, 1H: H at position 10); 5.66 (d, J=7, 1H: H at position 2); 7.49(t, J=7.5, 2H: OCOC₆H₅ H at the meta position); 7.63 (t, J=7.5, 1H:OCOC₆H₅ H at the para position); 8.12 (d, J=7.5, 2H: OCOC₆H₅ H at theortho position).

4α-Acetoxy-2α-benzoyloxy-5β, 20-epoxy-1β-hydroxy-10β-ethoxy-9-oxo7β,13α-bis(triethylsilyloxy)-11-taxene (or10β-ethoxy-10-deacetoxy-7,13-bis(triethylsilyl)baccatin III) wasprepared in the following manner:

93 mg of sodium hydride at a concentration of 50% by weight of liquidparaffin were added portionwise to a solution, maintained under an argonatmosphere, at a temperature in the region of 20° C., of 1 g of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β,10β-dihydroxy-9-oxo-7β,13α-bis(triethylsilyloxy)-11-taxene in 3 cm³ ofiodoethane and 4 cm³ of dimethylformamide. The solution was keptstirring for 17 hours at a temperature in the region of 20° C., and 93mg of sodium hydride at a concentration of 50% by weight in liquidparaffin was then added portionwise. After 50 minutes at a temperaturein the region of 20° C., the reaction mixture was diluted with 100 cm³of ethyl acetate and 10 cm³ of saturated aqueous ammonium chloridesolution. The organic phase was separated after settling had taken placeand washed with six times 10 cm³ of distilled water and then 10 cm³ ofsaturated aqueous sodium chloride solution, dried over magnesiumsulphate, filtered through sintered glass and concentrated to drynessunder reduced pressure (2.7 kPa) at a temperature in the region of 40°C. 1.2 g of a yellow foam were thereby obtained, which product waspurified by chromatography at atmospheric pressure on 150 g of silica(0.063-0.2 mm) contained in a column 3.5 cm in diameter, eluting with anethyl acetate/dichloromethane (2.98, then 5.95 by volume) mixture andcollecting 15-cm³ fractions. Fractions containing only the desiredproducts were pooled and concentrated to dryness under reduced pressure(0.27 kPa) at 40° C. for 2 hours. 379.2 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β,10β-dihydroxy-9-oxo-7β,13α-bis(triethylsilyloxy)-11-taxene were thereby obtained in the form ofa pale yellow foam and 430 mg of 4α-acetoxy-2α-benzoyloxy-5β,20-expoxy-1β-hydroxy-1β-ethoxy-9-oxo-7β,13α-bis(triethylsilyloxy-11-taxene were thereby obtained in the form ofa white foam, the characteristics of which 10-β-ethoxy product were asfollows:

¹H NMR spectrum (400 MHz; CDCl₃, chemical shifts δ in ppm, couplingconstant J in Hz): 0.57 and 0.70 (2 mts, 6H each; ethyl CH₂); 0.97 and1.03 (2 t, J=7.5, 9H each: ethyl CH₃): 1.13 (s, 3H: CH₃): 1.20 (s, 3H:CH₃); 1.29 (t, J=7.5, 3H: CH₃ of ethoxy at position 10); 1.58 (s, 1H: OHat position 1); 1.66 (s, 3H: CH₃); 1.89 and 2.58 (2 mts, 1H each: CH₂ atposition 2); 2.03 (s, 3H: CH₃); 2.13 and 2.23 (2 dd, J=16 and 9, 1Heach: CH₂ at position 14); 2.30 (s, 3H: COCH₃); 3.53 (mt, 2H: CH₂ ofethoxy at position 10); 3.84 (d, J=7, 1H: H at position 3); 4.14 and4.30 (2 d, J=8.5, 1H each: CH₂ at position 20); 4.43 (dd, J=11 and 6.5,1H: H at position 7); from 4.90 to 5.00 (mt, 2H: H at position 13 and Hat position 5); 5.01 (s, 1H, H at position 10); 5.61 (d, J=7, 1H: atposition 2); 7.48 (t, J=7.5, 2H: OCOC₆H₅ H at the meta position); 7.61(t, J=7.5, 1H: OCOC₆H₅ H at the para position); 8.10 (d, J=7.5, 2H:OCOC₆H₅ H at the ortho position).

EXAMPLE 4

65 mg of dicyclohexylcarbodiimide and then 7 mg of4-(N,N-dimethylaminopyridine were added successively at a temperature inthe region of 20° C. to a suspension containing 115 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-10β-(1-propyl)oxy-1β,13α-dihydroxy-7β-methoxy-9-oxo-11-taxene and 100 mg of(2R,4S,5R)-3-tert-butoxycarbonyl-2-(4-methoxyphenyl-4-phenyl-1,3-oxazolidine-5-carboxylicacid in 1 cm³ of anhydrous toluene. The suspension obtained was stirredat a temperature in the region of 20° C. under an argon atmosphere for 1hour, and then purified by direct application to a column forchromatography at atmospheric pressure on 30 g of silica (0.063-0.2 mm)contained in a column 2.5 cm in diameter (elution gradient: ethylacetate/dichloromethane from 2.98 to 10:90 by volume), collecting 10-cm³fractions. Fractions containing only the desired product were pooled andconcentrated to dryness under reduced pressure (2.7 kPa) at 40° C. for 2hours. 276.2 mg of a white solid were thereby obtained, which productwas purified by reparative thin-layer chromatography: 10 Merckpreparative silica gel 60F₂₅₄ plates, thickness 0.5 mm, application insolution in dichloromethane, eluting with a methanol/dichloromethane(3:97 volume) mixture. After elution of the zones corresponding to themain products with a methanol/dichloromethane (15:85 by volume) mixture,filtration through cotton wool and then evaporation of the solventsunder reduced pressure (2.7 kPa) at a temperature in the region of 40°C., 84.8 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-10β-(1-propyl)oxy-1β-hydroxy-7β-methoxy-9-oxo-11-taxen-13α-yl(2R,4S,5R)-3-tert-butoxycarbonyl-2-(4-methoxyphenyl)-4-phenyl-1,3-oxazolidine-5-carboxylatewere obtained in the form of a white foam, the characteristics of whichwere as follows:

¹H NMR spectrum (300 MHz; CDCl₃; chemical shifts δ in ppm; couplingconstants J in Hz): 0.97 (t, J=7, 3H: propyl CH₃) 1.07 (s, 9H: C(CH₃)₃);1.19 (s, 6H: CH₃); from 1.50 to 1.80 (mt, 3H: OH at position 1 andcentral CH₂ of propyl); 1.60 (s, 3H: CH₃); 1.70 (s, 3H: CH₃); 1.78 and2.63 (2 mts, 1H each: CH₂ at position 6); 1.82 (unres. comp. 3H: COCH₃);2.07 and 2.19 (2 dd, J=16 and 9, 1H each: CH₂ at postion 14); 3.26 (s,3H: OCH₃); 3.30 and 3.58 (2 mts, 1H each: propyl OCH₂); 3.73 (d, J=7.5,1H: H at position 3); 3.81 (s, 3H: ArOCH₃); 3.81 (mt, 1H: H at position7); 4.09 and 4.23 (2 d, J=8.5, 1H each: CH₂ at position 20); 4.57 (d,J=4.5, 1H: H at position 2′); 4.79 (s, 1H: H at position 10); 4.90(broad d, J=10, 1H: H at position 5); 5.40 (unres. comp. 1H: H atposition 3′); 5.58 (d, J=7.5, 1H: H at position 2); 6.13 (broad t, J=9,1H: H at position 13); 6.40 (spread unres. comp. 1H: H at position 5′);6.92 (d, J=8.5, 2H: aromatic H at the ortho position with respect toOCH₃); from 7.30 to 7.60 (mt, 9H: aromatic H at position 3′-aromatic Hat the meta position with respect to OCH₃ and OCOC₆H₅ meta H); 7.63 (t,J=7.5, 1H: OCOC₆H₅ H at the para position); 8.03 (d, J=7.5, 2H: OCOC₆H₅at the ortho position).

4α-Acetoxy-2α-benzoyloxy-5β,20-epoxy-1β-(1-propyl)oxy-1β-hydroxy-7β-methoxy-9-oxo-11-taxen-13α-yl(2R,3S)-3-tert-butoxycarbonylamino-2-hydroxy-3-phenylpropionate wasprepared in the following manner:

A solution of 84 mg of 4α-acetoxy-2α-benzoyloxy-5β,20-expoxy-10β-(1-propyl)oxy-1β-hydroxy-7β-methoxy-9-oxo-11-taxen-13α-yl(2R,4S,5R)-3-tert-butoxy-carbonyl-2-(4-methoxyphenyl)-4-phenyl-1,3-oxazolidine-5-carboxylatein 0.84 cm³ of ethyl acetate and 0.0071 cm³ of concentrated 37%hydrochloric acid was kept stirring at a temperature in the region of20° C. for 1 hour under an argon atmosphere. The reaction mixture wasthen purified by preparative thin-layer chromatography: application ofthe crude reaction mixture to 6 Merck preparative silica gel 60F₂₅₄plates, thickness 0.5 mm, eluting with amethanol/acetonitrile/dichloromethane (3:7:90 by volume) mixture. Afterelution of the zone corresponding to the main product with amethanol/dichloromethane (15:85 by volume) mixture, filtration throughcotton wool and then evaporation of the solvents under reduced pressure(2.7 kPa) at a temperature in the region of 40° C., 27 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-10β-(1-propyl)oxy-1β-hydroxy-7β-methoxy-9-oxo-11-taxen-13α-yl(2R,3S)-3-tert-butoxycarbonylamino-2-hydroxy-3-phenyl-propionate wereobtained in the form a white foam, the characteristics of which are asfollows:

¹H NMR spectrum (400 MHz; CDCl₃; chemical shifts δ in ppm; couplingconstants J in Hz);: 0.99 (t, J=7, 3H: propyl CH₃); 1.22 (s, 3H: CH₃);1.25 (s, 3H: CH₃); 1.38 (s, 9H: C(CH₃)₃; 1.64 (s, 1H: OH at position 1);1.69 (mt, 2H: central CH₂ of propyl): 1.73 (s, 3H: CH₃); 1.80 and 2.70(2 mts, 1H each: CH₂ at position 6); 1.88 (s, 3H: CH₃); 2.30 (mt, 2H:CH₂ at position 14); 2.38 (s, 3H: COCH₃); 3.31 (s, 3H: OCH₃); 3.36 and3.64 (2 mts, 1H each: propyl OCH₂); 3.44 (unres. comp. 1H: OH atposition 2′); 3.84 (d, J=7.5, Hz, 1H: at position 3); 3.87 (dd, J=11 and6.5, 1H: H at position 7); 4.18 and 4.30 (2 d, J=8.5, 1H each: CH₂ atposition 20); 4.64 (mt, 1H: H at position 2′); 4.89 (s, 1H: H atposition 10); 4.98 (broad d, J=10, 1H: H at position 5); 5.28 (broad d,J=10, 1H: H at position 3′); 5.42 (d, J=10, 1H: CONH); 5.64 (d, J=7.5,1H: H at position 2): 6.22 (broad t, J=9, 1H: H at position 13); from7.25 to 7.45 (mt, 5H: aromatic H at position 3′); 7.50 (d, J=7.5, 2H:OCOC₆H₅ H at the meta position); 7.61 (t, J=7.5, 1H: OCOC₆H₅ H at thepara position); 8.12 (d, J=7.5, 2H: OCOC₆H₅ H at the ortho position).

4α-Acetoxy-2α-benzoyloxy-5β, 20-epoxy-10β-(1-propyl)oxy-1β,13α-dihydroxy-7β-methoxy-9-oxo-11-taxene (or10β-(1-propyl)oxy-7β-methoxy-10-deacetoxybaccatin III) was prepared inthe following manner:

30 mg of sodium hydride at a concentration of 50% by weight in liquidparaffin were added portionwise to a solution, maintained under an argonatmosphere, at a temperature in the region of 0° C., of 165 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β,7β,13α-trihydroxy-10β-(1-propyl)oxy-9-11-taxenein 1.7 cm³ of iodomethane and 1 cm³ of dimethylformamide. After 30minutes at a temperature in the region of 0° C., the reaction mixturewas diluted with 40 cm³ of ethyl acetate, 5 cm³ of distilled water and 7cm³ of saturated aqueous ammonium chloride solution. After settling hadtaken place, the organic phase was separated and washed with three times7 cm³ of distilled water and then 7 cm³ of saturated aqueous sodiumchloride solution, dried over magnesium sulphate, filtered throughsintered glass and concentrated to dryness under reduced pressure (2.7kPa) at a temperature in the region of 40° C., 224 mg of the yellowsolid were thereby obtained, which product was purified bychromatography at atmospheric pressure on 20 g of silica (0.063-2 mm)contained in column 2.5 cm in diameter (elution gradient: ethylacetate/dichloromethane from 0.100 to 15.85 by volume), collecting10-cm³ fractions. Fractions containing only the desired product werepooled and concentrated to dryness under reduced pressure (2.7 kPa) at40° C. for 2 hours. 117.5 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-10β-(1-propyl)oxy-1β,13α-dihydroxy-7β-methoxy-9-oxo-11-taxenewere thereby obtained in the form of a white foam, the characteristicsof which were as follows:

¹H NMR spectrum (300 MHz; CDCl₃; chemical shifts δ ppm, couplingconstants J in Hz): 0.98 (t, J=7, 3H: propyl CH₃); 1.05 (s, 3H: CH₃);1.19 (s, 3H: CH₃); from 1.60 to 1.80 (mt, 2H: central CH₂ of propyl);from 1.65 to 1.85 and 2.66 (2 mts, 1H each; CH₂ at position 6 ); 1.72(s, 3H: CH₃); 2.10 (s, 3H: CH₃): from 2.05 to 2.35 (mt, 2H: cH₂ atposition 14); 2.28 (s, 3H: COCH₃); 3.32 (s, 3H: OCH₃); 3.45 and 3.65 (2mts, 1H each: propyl OCH₂); 3.92 (d, J=7.5, 1H: H3); 3.93 (dd, J=11 and6, 1H: H at position 7); 4.16 and 4.32 (2 d, J=8.5, 1H each: CH₂ atposition 20); 4.90 (mt, 1H: H at position 13); 4.94 (s, 1H: H atposition 10); 5.03 (broad d, J=10, 1H: H at position 5); 5.60 (d, J=7.5,1H: H at position 2); 7.48 (t, J=7.5, 2H: OCOC₆H₅ H at the metaposition); 7.62 (t, J=7.5, 1H: OCOC₆H₅ H at the para position); 8.11 (d,J=7.5, 2H: OCOC₆H₅ at the ortho position).

4α-Acetoxy-2α-benzoyloxy-5β,20-epoxy-1β,7β,13α-trihydroxy-10β-(1-propyl)oxy-9-oxo-11-taxene (or10β-(1-propyl)oxy-10-deacetoxybaccatin III) was prepared in thefollowing manner:

8.75 cm³ of hydrogen fluoride/triethylamine complex (3HF, Et₃N) wereadded to a solution, maintained under an argon atmosphere, at atemperature in the region of 20° C., of 585 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β-hydroxy-10β-(1-propyl)oxy-9-7β,13α-bis(triethylsilyloxy)-11-taxenein 6 cm³ of dichloromethane. After 24 hours at a temperature in theregion of 20° C., the reaction mixture was diluted with 30 cm³ ofdichloromethane and poured into a suspension of 30 cm³ of supersaturatedaqueous sodium hydrogen carbonate solution maintained at a temperaturein the region of 0° C. After dilution with 10 cm³ of distilled water andwhen settling had taken place, the aqueous phase was separated andre-extracted with twice 20 cm³ of diethyl ether. The organic phases werecombined, washed with 20 cm³ of distilled water and 20 cm³ of saturatedaqueous sodium chloride solution, dried over magnesium sulphate,filtered through magnesium sulphate and concentrated to dryness underreduced pressure (2.7 kPa) at a temperature in the region of 40° C. 500mg of a pale yellow foam were thereby obtained, which product waspurified by chromatography at atmospheric pressure on 40 g of silica(0.063-0.2 mm) contained in a column 2.5 cm in diameter, eluting with amethanol/dichloromethane (2:98 by volume) mixture and collecting 15-cm³fractions. Fractions containing only the desired product were pooled andconcentrated to dryness under reduced pressure (2.7 kPa) at 40° C. for 2hours. 373.8 mg of4α-acetoxy-2α-benzoyloxy-5β,20-expoxy-1β,7β,13α-trihydroxy-10β-(1-propyl)oxy-9-oxo-11-taxenewere thereby obtained in the form of a white solid, the characteristicsof which were as follows:

¹H NMR spectrum (300 MHz: CDCl₃; chemical shifts 67 in ppm, couplingconstants J in Hz): 0.95 (t, J=7, 3H: propyl CH₃); 1.06 (s, 3H: CH₃);1.22 (s, 3H: CH₃); 1.45 (d, J=7.5, 1H: OH at position 7); from 1.60 to1.80 (mt, 2H: central CH₂ of propyl); 1.67 (s, 3H: CH₃); 1.83 and 2.62(2 mts, 1H each: CH₂ at position 6); 2.05 (s, 3H: CH₃); 2.05 (mt, 1H: OHat position 13); 2.27 (limiting AB, 2H: CH₂ at position 4); 2.28 (s, 3H:COCH₃); 3.40 and 3.57 (2 mts, 1H each: propyl OCH₂); 3.97 (d, J=7.5, 1H:H at position 3); 4.15 and 4.30 (2 d, J=8.5, 1H each: CH₂ at position20); 4.28 (mt, 1H: H at position 7); 4.90 (mt, 1H: H at position 13);4.98 (broad d, J=10, 1H: H at position 5); 5.03 (s, 1H: H at position10); 5.65 (d, J=7.5, 1H: H at position 2); 7.50 (t, J=7.5, 2H: OCOC₆H₅at the meta position); 7.60 (t, J=7.5, 1H: OCOC₆H₅ H at the paraposition); 8.00 (d, J=7.5, 2H: OCOC₆H₅ H at the ortho position).

4α-Acetoxy-2α-benzoyloxy-5β,20-expoxy-1β-hydroxy-10β-(1-propyl)oxy-9-oxo-7β,13α-bis(triethyl-silyloxy)-11-taxene(or 10β-(1-propyl)oxy-10-deacetoxy-7,13-bis(triethylsilyl)baccatin III)was prepared in the following manner:

93 mg of sodium hydride at a concentration of 50% by weight in liquidparaffin were added portionwise to a solution, maintained under an argonatmosphere, at a temperature in the region of 20° C., of 1 g of4α-acetoxy-2α-benzoyloxy-5β,20-expoxy-1β,10β-dihydroxy-9-oxo-7β,13α-bis(triethylsilyoxy)-11-taxenein 3 cm³ of iodoethane and 4 cm³ of dimethylformamide. The solution waskept stirring for 19 hours at a temperature in the region of 20° C., and93 mg of sodium hydride at a concentration of 50% by weight in liquidparaffin were then added portionwise. After 3 hours at a temperature inthe region of 20° C., the reaction mixture was diluted with 100 cm³ ofethyl acetate and 10 cm³ of saturated aqueous ammonium chloridesolution. The organic phase was separated after settling had taken placeand washed with six times 10 cm³ of distilled water and then 10 cm³ ofsaturated aqueous sodium chloride solution, dried over magnesiumsulphate, filtered through sintered glass and concentrated to drynessunder reduced pressure (2.7 kPa) at a temperature in the region of 40°C., 1.32 g of a pale yellow foam were thereby obtained, which productwas purified by chromatography at atmospheric pressure on 150 g ofsilica (0.063-0.2 mm) contained in a column 3.5 cm in diameter, elutingwith an ethyl acetate/dichloromethane (2:98, then 5:95 by volume)mixture and collection 15-cm³ fractions. Fractions containing only thedesired products were pooled and concentrated to dryness under reducedpressure (0.27 kPa) at 40° C. for 2 hours. 376.3 mg of4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β,10β-dihydroxy-9-oxo-7β,13α-bis(triethylislyoxy)-11-taxenewere thereby obtained in the form of a pale yellow foam and 395.3 mg of4α-acetoxy-2α-benzoyloxy-5β,20-expoxy-1β-hydroxy-10β-(1-propyl)oxy-9-oxo-7β,13α-bis(triethylsilyloxy)-11-taxenewere thereby obtained in the form of a pale yellow foam, thecharacteristics of which were as follows:

¹H NMR spectrum (400 MHz; CDCl₃; chemical shifts δ in ppm; couplingconstants J in Hz): 0.57 and 0.70 (2 mts, 6H each; ethyl CH₂): 0.94 and1.03 (2 t, J=7.5, 9H each: ethyl CH₃); 0.94 (t, J=7.5, 3H: propyl CH₃);1.14 (s, 3H: CH₃); 1.21 (s, 3H: CH₃); 1.67 (s, 3H: CH₃); 1.69 (mt, 2H:central CH₂ of propyl); 1.88 and 2.48 (2 mts, 1H each: CH₂ at position6); 2.03 (s, 3H: CH₃); 2.14 and 2.23 (2 dd, J=16 and 9, 1H each: CH₂ atposition 14); 2.30 (s, 3H: COCH₃); 3.40 (mt, 2H: propyl OCH₂); 3.84 (d,J=7.5, 1H: H at position 3); 4.16 and 4.30 (2 d, J=8.5, 1H each: CH₂ atposition 20); 4.44 (dd, J=11 and 6.5, 1H: H at position 7); 4.96 (broadd, J=10 Hz, 1H: H5); 4.97 (s, 1H: H 10); 4.99 (broad t, J=9 Hz, 1H: H atposition 13); 5.62 (d, J=7.5, 1H: H at position 2); 7.48 (t, J=7.5, 2H:OCOC₆H₅ H at the meta position); 7.60 (t, J=7.5, 1H: OCOC₆H₅ H at thepara position); 8.10 (d, J=7.5, 2H: OCOC₆H₅ H at the ortho position).

The new products of general formula (I) in which Z represents a radicalof general formula (II) manifest significant inhibitory activity withrespect to abnormal cell proliferation, and possess therapeuticproperties permitting the treatment of patients having pathologicalconditions associated with abnormal cell proliferation. The pathologicalconditions include the abnormal cell proliferation of malignant ornon-malignant cells of various tissues and/or organs, comprising,without implied limitation, muscle, bone or connective tissue, the skin,brain, lungs, sex organs, the lymphatic or renal systems, mammary orblood cells, liver, the digestive system, pancreas and thyroid oradrenal glands. These pathological conditions can also includepsoriasis, solid tumours, cancers of the ovary, breast, brain, prostate,colon, stomach, kidney or testicles, Kaposi's sarcoma,cholangiocarcinoma, choriocarcinoma, neuroblastoma, Wilm's tumor,Hodgkin's disease, melanoma, multiple myeloma, chronic lymphocyticleukemia and acute or chronic granulocytic lymphoma.

The new products according to the invention are especially useful forthe treatment of cancer of the ovary. The products according to theinvention may be used to prevent or delay the appearance or reappearanceof the pathological conditions, or to treat these pathologicalconditions.

The products according to the invention may be administered to a patientaccording to different dosage forms suited to the chosen administrationroute, which is preferable the parenteral route. Parenteraladministration comprises intravenous, intraperitoneal, intramuscular orsubcutaneous administration. Intraperitoneal or intravenousadministration is more especially preferred.

The present invention also comprises pharmaceutical compositionscontaining at least one product of general formula (I), in a sufficientamount suitable for use in human or veterinary therapy. The compositionsmay be prepared according to the customary methods, using one or morepharmaceutically acceptable adjuvants, vehicles or excipients. Suitablevehicles include diluents, sterile aqueous media and various non-toxicsolvents. Preferably, the compositions take the form of aqueoussolutions or suspension, injectable solutions which can containemulsifying agents, colourings, preservatives or stabilizers. However,the compositions can also take the form of tablets, pills, powders orgranules which can be administered orally.

The choice of adjuvants or excipients may be determined by thesolubility and the chemical properties of the product, the particularmode of administration and good pharmaceutical practice.

For parenteral administration, sterile, aqueous or non-aqueous solutionsor suspensions are used. For the preparation of non-aqueous solutions orsuspensions, natural vegetable oils such as olive oil, sesame oil orliquid petroleum, or injectable organic esters such as ethyl oleate, maybe used. The sterile aqueous solutions can consists of a solution of apharmaceutically acceptable salt dissolved in water. The aqueoussolutions are suitable for intravenous administration provided the pH isappropriately adjusted and the solution is made isotonic, for examplewith a sufficient amount of sodium chloride or glucose. Thesterilization may be carried out by heating or by any other means whichdoes not adversely affect the composition.

It is clearly understood that all the products participating in thecompositions according to the invention must be pure and non-toxic inthe amounts used.

The compositions can contain at least 0.01% of therapeutically activeproduct. The amount of active product in a composition is such that asuitable dosage can be prescribed. Preferably, the compositions areprepared in such a way that a single does contains from 0.01 to 1000 mgapproximately of active product for parental administration.

The therapeutic treatment may be performed concurrently with othertherapeutic treatments including antineoplastic drugs, monoclonalantibodies, immunotherapy or radiotherapy or biological responsemodifiers. The response modifiers include, without implied limitation,lymphoines and cytokines such as interleukins, interferons (α, βor δ)and TNF.

Other chemotherapeutic agents which are useful in the treatment ofdisorders due to abnormal cell proliferation include, without impliedlimitation, alkylating agents, for instance nitrogen mustards such asmechlorethamine, chyclophosphamide, melphalan and chlorambucil, alkylsulphonates such as busulfan, nitrosoureas such as carmustine,lomustine, semustine and streptozocin, triazenes such as dacarbazine,antimetabolites such as folic acid analogues, for instance methotrexate,pyrimidine analogues such as fluorouracil and cytarabine, purineanalogues such as mercaptopurine and thioguanine, natural products, forinstance vinca alkaloids such as vinblastine, vincristine and vindesine,epipodophyllotoxins such as etoposide and teniposide, antibiotics suchas dactinomycin, danuorubicin, doxorubicin, bleomycin, plicamycin andmitomycin, enzymes such as L-asparaginase, various agents such ascoordination complexes of platinum, for instance cisplatin, substitutedureas such as hydroxyurea, methylhydrazine derivatives such asprocarbazine, adrenocortical suppressants such as mitotane andaminoglutethimide, hormones and antagonists such asadrenocorticosteroids such as prednisone, progestins such ashydroxyprogesterone caproate, methoxyprogesterone acetate and megestrolacetate, oestrogens such as diethylstiboestrol and ethylnyloestradiol,antioestrogens such as tamoxifen, and androgens such as testosteronepropionate and fluoxymesterone.

The doses used for carrying out the methods according to the inventionare those which permit a prophylactic treatment or a maximum therapeuticresponse. The doses vary according to the administration form, theparticular product selected and features distinctive to the subject tobe treated. In general, the doses are those which are therapeuticallyeffective for the treatment of disorders due to abnormal cellproliferation.

The products according to the invention may be administered as often asnecessary to obtain the desired therapeutic effect. Some patients mayrespond rapidly to relatively high or low doses, and then require low orzero maintenance doses. Generally, low doses will be used at thebeginning of the treatment and, if necessary, increasingly strongerdoses will be administered until an optimum effect is obtained.

For other patients, it may be necessary to administer maintenance doses1 to 8 times a day, and preferably 1 to 4 times, according to thephysiological requirements of the patient in question. It is alsopossible that some patients may require the use of only one to two dailyadministrations.

In man, the doses generally range form 0.01 to 200 mg/kg. Forintraperitioneal administration, the doses will generally range from 0.1to 100 mg/kg, preferably from 0.5 to 50 mg/kg and still morespecifically from 1 to 10 mg/kg. For intravenous administration, thedoses generally range from 0.1 to 50 mg/kg, preferably from 0.1 to 5mg/kg and still more specifically from 1 to 2 mg/kg. It is understoodthat, in order to choose the most suitable dosage, account should betaken of the administration route, the patient's weight, general stateof health and age and all factors which may influence the efficacy ofthe treatment.

The example which follows illustrates a composition according to theinvention.

EXAMPLE

40 mg of the product obtained in Example 1 are dissolved in 1 cm³ ofEmulphor EL 620 and 1 cm³ of ehtanol, and the solution is then dilutedby adding 18 cm³ of physiological saline. The composition isadministered by perfusion over 1 hour by introduction in physiologicalsolution.

We claim:
 1. A taxoid of the formula (I):

in which Z represents a hydrogen atom or a radical of formula (II):

in which: R₁ represents a benzoyl radical optionally substituted withone or more identical or different atoms or radicals selected fromhalogen atoms, alkyl radicals containing 1 to 4 carbon atoms, alkoxyradicals containing 1 to 4 carbon atoms, and trifluoromethyl radicals, athenoyl radical, a furoyl radical, or a radical R₂—O—CO— in which R₂represents: an alkyl radical containing 1 to 8 carbon atoms, an alkenylradical containing 2 to 8 carbon atoms, an alkynyl radical containing 3to 8 carbon atoms, a cycloalkyl radical containing 3 to 6 carbon atoms,a cycloalkenyl radical containing 4 to 6 carbon atoms or a bicycloalkylradical containing 7 to 10 carbon atoms, these radicals being optionallysubstituted with one or more substituents selected from halogen atoms;hydroxyl radicals; alkoxy radicals containing 1 to 4 carbon atoms;dialkylamino radicals in which each alkyl portion contains 1 to 4 carbonatoms; piperidino radicals; morpholino radicals; 1-piperazinyl radicalsoptionally substituted at position 4 with an alkyl radical containing 1to 4 carbon atoms or with a phenylalkyl radical in which the alkylportion contains 1 to 4 carbon atoms; cycloalkyl radicals containing 3to 6 carbon atoms; cycloalkenyl radicals containing 4 to 6 carbon atoms;phenyl radicals optionally substituted with one or more atoms orradicals selected from halogen atoms, alkyl radicals containing 1 to 4carbon atoms and alkoxy radicals containing 1 to 4 carbon atoms; cyanoradicals; carboxyl radicals; and alkoxycarbonyl radicals in which thealkyl portion contains 1 to 4 carbon atoms, a phenyl or α- or β-naphthylradical optionally substituted with one or more atoms or radicalsselected from halogen atoms; alkyl radicals containing 1 to 4 carbonatoms; and alkoxy radicals containing 1 to 4 carbon atoms, a 5-memberedaromatic heterocyclic radical, or a saturated heterocyclic radicalcontaining 4 to 6 carbon atoms, optionally substituted with one or morealkyl radicals containing 1 to 4 carbon atoms, R₃ represents anunbranched or branched alkyl radical containing 1 to 8 carbon atoms, anunbranched or branched alkenyl radical containing 2 to 8 carbon atoms,an unbranched or branched alkynyl radical containing 2 to 8 carbonatoms, a cycloalkyl radical containing 3 to 6 carbon atoms, a phenyl onα- or β-naphthyl radical optionally substituted with one or moreidentical or different atoms or radicals selected from halogen atoms,alkyl, alkenyl, alkynyl, aryl, aralkyl, alkoxy, alkylthio, aryloxy,arylthio, hydroxyl, hydroxyalkyl, mercapto, formyl, acyl, acylamino,aroylamino, alkoxycarbonylamino, amino, alkylamino, dialkylamino,carboxyl, alkoxycarbonyl, carbamoyl, alkylcarbamoyl, dialkylcarbamoyl,cyano, nitro and trifluoromethyl radicals, or a 5-membered aromaticheterocyclic containing one or more identical or different hetero atomsselected from nitrogen, oxygen and sulphur atoms and optionallysubstituted with one or more identical or different substituentsselected from halogen atoms, alkyl, aryl, amino, alkylamino,dialkylamino, alkoxycarbonylamino, acyl, arylcarbonyl, cyano, carboxyl,carbamoyl, alkylcarbamoyl, dialkylcarbamoyl and alkoxycarbonyl radicals,with the proviso that, in the substituents of the phenyl, α- orβ-naphthyl and aromatic heterocyclic radicals in the definitions of R₂and R₃, the alkyl radicals and the alkyl portions of the other radicalscontain 1 to 4 carbon atoms, and the alkenyl and alkynyl radicalscontain 2 to 8 carbon atoms, and the aryl radicals are phenyl or α- orβ-naphthyl radicals, R₄ represents an alkoxy radical containing 1 to 6carbon atoms in an unbranched or branched chain, and R₅ represents analkoxy radical containing 1 to 6 carbon atoms in an unbranched orbranched chain.
 2. A taxoid according to claim 1, wherein Z represents ahydrogen atom or a radical of formula (II) in which R₁ represents abenzoyl radical or a radical R₂—O—CO— in which R₂ represents atert-butyl radical, and R₃ represents an alkyl radical containing 1 to 6carbon atoms, an alkenyl radical containing 2 to 6 carbon atoms; acycloalkyl radical containing 3 to 6 carbon atoms; a phenyl radicaloptionally substituted with one or more identical or different atoms orradical selected from halogen atoms, alkyl, alkoxy, dialkylamino,acylamino, alkoxycarbonylamino and trifluoromethyl radicals, or a2-furyl, 3- furyl, 2-thienyl, 3-thienyl, 2-thiazolyl, 4-thiazolyl, or5-thiazolyl radical.
 3. A taxoid according to claim 1, wherein Zrepresents a hydrogen atom or a radical of formula (II) in which R₁represents a benzoyl radical or a radical R₂—O—CO— in which R₂represents a tert-butyl radical, R₃ represents an isobutyl, isobutenyl,butenyl, cyclohexyl, phenyl, 2-furyl, 3-furyl, 2-thienyl, 3-thienyl,2-thiazolyl, 4-thiazolyl or 5-thiazolyl radical, and R₄ and R₅, whichmay be identical or different, each represents a methoxy, ethoxy orpropoxy radical.
 4. A taxoid according to claim 1, wherein when R₂represents a 5-membered aromatic heterocyclic radical, said radical is afuryl or thienyl radical. 5.4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-10β-ethoxy-1β-hydroxy-7β-methoxy-9-oxo-11-taxen-13α-yl(2R,3S)-3-tert-butoxycarbonylamino-2-hydroxy-3-phenylpropionate.6.4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-10β-(1-propyl)oxy-1β-hydroxy-7β-methoxy-9-oxo-11-taxen-13α-yl(2R,3S)-3-tert-butoxycarbonylamino-2-hydroxy-3-phenyl-propionate.7. A pharmaceutical composition comprising at least one productaccording to claim 1 wherein Z represents a radical formula (II), incombination with one or more pharmaceutically acceptable diluents oradjuvants and optionally one or more compatible and pharmacologicallyactive compounds.
 8. A pharmaceutical composition comprising at leastthe product according to claim 5 in combination with one or morepharmaceutically acceptable diluents or adjuvants and optionally one ormore compatible and pharmacologically active compounds.
 9. Apharmaceutical composition comprising at least the product according toclaim 6 in combination with one or more pharmaceutically acceptablediluents or adjuvants and optionally one or more compatible andpharmacologically active compounds.
 10. An ester of the formula (V):

wherein R₁ represents a benzoyl radical optionally substituted with oneor more identical or different atoms or radicals selected from halogenatoms, alkyl radicals containing 1 to 4 carbon atoms, alkoxy radicalscontaining 1 to 4 carbon atoms, and trifluoromethyl radicals, a thenoylradical, a furoyl radical, or a radical R₂—O—CO— in which R₂ represents;an alkyl radical containing 1 to 8 carbon atoms, an alkenyl radicalcontaining 2 to 8 carbon atoms, an alkynyl radical containing 3 to 8carbon atoms, a cycloalkyl radical containing 3 to 6 carbon atoms, acycloalkenyl radical containing 4 to 6 carbon atoms or a bicycloalkylradical containing 7 to 10 carbon atoms, these radicals being optionallysubstituted with one or more substituents selected from halogen atoms;hydroxyl radicals; alkoxy radicals containing 1 to 4 carbon atoms;dialkylamino radicals in which each alkyl portion contains 1 to 4 carbonatoms; piperidino radicals; morpholino radicals; 1-piperazinyl radicalsoptionally substituted at position 4 with an alkyl radical containing 1to 4 carbon atoms or with a phenylalkyl radical in which the alkylportion contains 1 to 4 carbon atoms; cycloalkyl radicals containing 3to 6 carbon atoms; cycloalkenyl radicals containing 4 to 6 carbon atoms;phenyl radicals optionally substituted with one or more atoms orradicals selected from halogen atoms, alkyl radicals containing 1 to 4carbon atoms and alkoxy radicals containing 1 to 4 carbon atoms; cyanoradicals; carboxyl radicals; and alkoxycarbonyl radicals in which thealkyl portion contains 1 to 4 carbon atoms, a phenyl or α- or β-naphthylradical optionally substituted with one or more atoms or radicalsselected from halogen atoms; alkyl radicals containing 1 to 4 carbonatoms; and alkoxy radicals containing 1 to 4 carbon atoms, a 5-memberedaromatic heterocyclic radical, or a saturated heterocyclic radicalcontaining 4 to 6 carbon atoms, optionally substituted with one or morealkyl radicals containing 1 to 4 carbon atoms, R₃ represents anunbranched or branched alkyl radical containing 1 to 8 carbon atoms, anunbranched or branched alkenyl radical containing 2 to 8 carbon atoms,an unbranched or branched alkynyl radical containing 2 to 8 carbonatoms, a cycloalkyl radical containing 3 to 6 carbon atoms, a phenyl orα- or β-naphthyl radical optionally substituted with one or more atomsor radicals selected from halogen atoms, alkyl, alkenyl, alkynyl, aryl,aralkyl, alkoxy, alkylthio, aryloxy, arylthio, hydroxyl, hydroxyalkyl,mercapto, formyl, acyl, acylamino, aroylamino, alkoxycarbonylamino,amino, alkylamino, dialkylamino, carboxyl, alkoxycarbonyl, carbamoyl,alkylcarbamoyl, dialkylcarbamoyl, cyano, nitro and trifluoromethylradicals, or or 5-membered aromatic heterocyclic containing one or moreidentical or different hetero atoms selected from nitrogen, oxygen andsulphur atoms and optionally substituted with one or more identical ordifferent substituents selected from halogen atoms, alkyl, aryl, amino,alkylamino, dialkylamino, alkoxycarbonylamino, acyl, arylcarbonyl,cyano, carboxyl, carbamoyl, alkylcarbamoyl, dialkylcarbamoyl andalkoxycarbonyl radicals, with the proviso that, in the substituents ofthe phenyl, α- or β-naphthyl and aromatic heterocyclic radicals in thedefinitions of R₂ and R₃, the alkyl radicals and the alkyl portions ofthe other radicals contain 1 to 4 carbon atoms, and the alkenyl andalkynyl radicals contain 2 to 8 carbon atoms, and the aryl radicals arephenyl or α- or β-naphthyl radicals. R₄ represents an alkoxy radicalcontaining 1 to 6 carbon atoms in an unbranched or branched chain, R₅represents an alkoxy radical containing 1 to 6 carbon atoms in anunbranched or branched chain, and either R₆ represents a hydrogen atomand R₇ represents a group protecting the hydroxyl function, or R₆ and R₇together form a saturated 5- or 6-membered heterocycle.
 11. An ester offormula (VII):

wherein R₃ represents an unbranched or branched alkyl radical containing1 to 8 carbon atoms, an unbranched or branched alkenyl radicalcontaining 2 to 8 carbon atoms, an unbranched or branched alkynylradical containing 2 to 8 carbon atoms, a cycloalkyl radical containing3 to 6 carbon atoms, a phenyl or α- or β-naphthyl radical optionallysubstituted with one or more atoms or radicals selected from halogenatoms, alkyl, alkenyl, alkynyl, aryl, aralkyl, alkoxy, alkylthio,aryloxy, arylthio, hydroxyl, hydroxyl, hydroxyalkyl, mercapto, formyl,acyl, acylamino, aroylamino, alkoxycarbonylamino, amino, alkylamino,dialkylamino, carboxyl, alkoxycarbonyl, carbamoyl, alkylcarbamoyl,dialkylcarbamoyl, cyano, nitro and trifluoromethyl radicals, or a5-membered aromatic heterocycle containing one or more identical ordifferent hetero atoms selected from nitrogen, oxygen and sulfur atomsand optionally substituted with one or more identical or differentsubstituents selected from halogen atoms, alkyl, aryl, amino,alkylamino, dialkylamino, alkoxycarbonylamino, acyl, arylcarbonyl,cyano, carboxyl, carbamoyl, alkylcarbamoyl, dialkylcarbamoyl andalkoxycarbonyl radicals, with the provision that, in the substituents ofthe phenyl, α- or β-naphthyl and aromatic heterocyclic radicals in thedefinitions of R₂ and R₃, the alkyl radicals and the alkyl portions ofthe other radicals contain 1 to 4 carbon atoms, and the alkenyl andalkynyl radicals contain 2 to 8 carbon atoms, and the aryl radicals arephenyl or α- or β-naphthyl radicals, R₄ represents an alkoxy radicalcontaining 1 to 6 carbon atoms in an unbranched or branched chain, andR₅ represents an alkoxy radical containing 1 to 6 carbon atoms in anunbranched or branched chain. 12.4α-Acetoxy-2α-benzoyloxy-5β,20-epoxy-1β-hydroxy-7β,10β-bis(methylthiomethoxy)-9-oxo-11-taxen-13α-yl(2R,4S,5R)-3-tert-butoxycarbonyl-2-(4-methoxyphenyl)-4-phenyl-1,3-oxazolidine-5-carboxylate.13. A taxoid of the formula (I):

in which: Z represents a hydrogen atom or a radical of formula (II):

in which: R₁ represents a benzoyl radical optionally substituted withone or more identical or different atoms or radicals selected fromhalogen atoms, alkyl radicals containing 1 to 4 carbon atoms, alkoxyradicals containing 1 to 4 carbon atoms, and trifluoromethyl radicals, athenoyl radical, a furoyl radical, or a radical R₂—O—CO— in which R₂represents: an alkyl radical containing 1 to 8 carbon atoms, an alkenylradical containing 2 to 8 carbon atoms, an alkynyl radical containing 3to 8 carbon atoms, a cycloalkyl radical containing 3 to 6 carbon atoms,a cycloalkenyl radical containing 4 to 6 carbon atoms or a bicycloalkylradical containing 7 to 10 carbon atoms, these radicals being optionallysubstituted with or more substituents selected from halogen atoms;hydroxyl radicals; alkoxy radicals containing 1 to 4 carbon atoms;dialkylamino radicals in which each alkyl portion contains 1 to 4 carbonatoms; piperidino radicals; morpholino radicals; 1-piperazinyl radicalsoptionally substituted at position 4 with an alkyl radical containing 1to 4 carbon atoms or with a phenylalkyl radical in which the alkylportion contains 1 to 4 carbon atoms; cycloalkyl radicals containing 3to 6 carbon atoms; cycloalkenyl radicals containing 4 to 6 carbon atoms;phenyl radicals optionally substituted with one or more atoms orradicals selected from halogen atoms, alkyl radicals containing 1 to 4carbon atoms and alkoxy radicals containing 1 to 4 carbon atoms; cyanoradicals; carboxyl radicals; and alkoxycarbonyl radicals in which thealkyl portion contains 1 to 4 carbon atoms. a phenyl or α- or β-naphthylradical optionally substituted with one or more atoms or radicalsselected from halogen atoms; alkyl radicals containing 1 to 4 carbonatoms; and alkoxy radicals containing 1 to 4 carbon atoms, a 5-memberedaromatic heterocyclic radical, or a saturated heterocyclic radicalcontaining 4 to 6 carbon atoms, optionally substituted with one or morealkyl radicals containing 1 to 4 carbon atoms, R₃ represents anunbranched or branched alkyl radical containing 1 to 8 carbon atoms, anunbranched or branched alkenyl radical containing 2 to 8 carbon atoms,an unbranched or branched alkynyl radical containing 2 to 8 carbonatoms, a cycloalkyl radical containing 3 to 6 carbon atoms, a phenyl orα- or β-naphthyl radical optionally substituted with one or moreidentical or different atoms or radicals selected from halogen atoms,alkyl, alkenyl, alkynyl, aryl, aralkyl, alkoxy, alkylthio, aryloxy,arylthio, hydroxyl, hydroxyalkyl, mercapto, formyl, acyl, acylamino,aroylamino, alkoxycarbonylamino, amino, alkylamino, dialkylamino,carboxyl, alkoxycarbonyl, carbamoyl, alkylcarbamoyl, dialkylcarbamoyl,cyano, nitro and trifluoromethyl radicals, or a 5-membered aromaticheterocycle containing one or more identical or different hereto atomsselected from nitrogen, oxygen and sulphur atoms and optionallysubstituted with one or more identical or different substituentsselected from halogen atoms, alkyl, aryl, amino, alkylamino,dialkylamino, alkoxycarbonylamino, acyl, arylcarbonyl, cyano, carboxyl,carbamoyl, alkylcarbamoyl, dialkylcarbamoyl and alkoxycarbonyl radicals,with the proviso that, in the substituents of the phenyl, α- orβ-naphthyl and aromatic heterocyclic radicals in the definitions of R₂and R₃, the alkyl radicals and the alkyl portions of the other radicalscontain 1 to 4 carbon atoms, and the alkenyl and alkynyl radicalscontain 2 to 8 carbon atoms, and the aryl radicals are phenyl or α- orβ-naphthyl radicals, R₄ represents an alkoxy radical containing 1 to 6carbon atoms in an unbranched or branched chain substituted with atleast one substituent selected from an alkylthio radical containing 1 to4 carbon atoms, and R₅ represents an alkoxy radical containing 1 to 6carbon atoms in an unbranched or branched chain substituted with atleast one substituent selected from an alkylthio radical containing 1 to4 carbon atoms.
 14. An ester of the formula (V):

wherein R₁ represents a benzoyl radical optionally substituted with oneor more identical or different atoms or radicals selected from halogenatoms, alkyl radicals containing 1 to 4 carbon atoms, alkoxy radicalscontaining 1 to 4 carbon atoms, and trifluoromethyl radicals, a thenoylradical, a furoyl radical, or a radical R₂—O—CO— in which R₂ represents;an alkyl radical containing 1 to 8 carbon atoms, an alkenyl radicalcontaining 2 to 8 carbon atoms, an alkynyl radical containing 3 to 8carbon atoms, a cycloalkyl radical containing 3 to 6 carbon atoms, acycloalkenyl radical containing 4 to 6 carbon atoms or a bicycloalkylradical containing 7 to 10 carbon atoms, these radicals being optionallysubstituted with one or more substituents selected from halogen atoms;hydroxyl radicals; alkoxy radicals containing 1 to 4 carbon atoms;dialkylamino radicals in which each alkyl portion contains 1 to 4 carbonatoms; piperidino radicals; morpholino radicals; 1-piperazinyl radicalsoptionally substituted at position 4 with an alkyl radical containing 1to 4 carbon atoms or with a phenylalkyl radical in which the alkylportion contains 1 to 4 carbon atoms; cycloalkyl radicals containing 3to 6 carbon atoms; cycloalkenyl radicals containing 4 to 6 carbon atoms;phenyl radicals optionally substituted with one or more atoms orradicals selected from halogen atoms, alkyl radicals containing 1 to 4carbon atoms and alkoxy radicals containing 1 to 4 carbon atoms; cyanoradicals; carboxyl radicals; and alkoxycarbonyl radicals in which thealkyl portion contains 1 to 4 carbon atoms, a phenyl or α- or β-naphthylradical optionally substituted with one or more atoms or radicalsselected from halogen atoms; alkyl radicals containing 1 to 4 carbonatoms; and alkoxy radicals containing 1 to 4 carbon atoms, a 5-memberedaromatic heterocyclic radical, or a saturated heterocyclic radicalcontaining 4 to 6 carbon atoms, optionally substituted with one or morealkyl radicals containing 1 to 4 carbon atoms, R₃ represents anunbranched or branched alkyl radical containing 1 to 8 carbon atoms, anunbranched or branched alkenyl radical containing 2 to 8 carbon atoms,an unbranched or branched alkynyl radical containing 2 to 8 carbonatoms, cycloalkyl radical containing 3 to 6 carbon atoms, a phenyl or α-or β-naphthyl radical optionally substituted with one or more atoms orradicals selected from halogen atoms, alkyl, alkenyl, alkynyl, aryl,aralkyl, alkoxy, alkylthio, aryloxy, arylthio hydroxyl, hydroxyalkyl,mercapto, formyl, acyl, acylamino, aroylamino, alkoxycarbonylamino,amino, alkylamino, dialkylamino, carboxyl, alkoxycarbonyl, carbamoyl,alkylcarbamoyl, dialkylcarbamoyl, cyano, nitro and trifluoromethylradicals, or a 5-membered aromatic heterocycle containing one or moreidentical or different hetero atoms selected from nitrogen, oxygen andsulphur atoms and optionally substituted with one or more identical ordifferent substituents selected from halogen atoms, alkyl, aryl, amino,alkylamino, dialkylamino, alkoxycarbonylamino, acyl, arylcarbonyl,cyano, carboxyl, carbamoyl, alkylcarbamoyl, dialkylcarbamoyl andalkoxycarbonyl radicals, with the proviso that, in the substituents ofthe phenyl, α- or β-naphthyl and aromatic heterocyclic radicals in thedefinitions of R₂ and R₃, the alkyl radicals and the alkyl portions ofthe other radicals contain 1 to 4 carbon atoms, and the alkenyl andalkynyl radicals contain 2 to 8 carbon atoms, and the aryl radicals arephenyl of α- or β-naphthyl radicals, R₄ represents an alkoxy radicalcontaining 1 to 6 carbon atoms in an unbranched or branched chainsubstituted with at least one substituent selected from an alkylthioradical containing 1 to 4 carbon atoms, R₅ represents an alkoxy radicalcontaining 1 to 6 carbon atoms in an unbranched or branched chainsubstituted with at least one substituent selected from an alkylthioradical containing 1 to 4 carbon atoms, and either R₆ represents ahydrogen atom and R₇ represents a group protecting the hydroxy function,or R₅ and R₇ together form a saturated 5- or 6-membered heterocycle. 15.An ester of formula (VII):

wherein R₃ represents an unbranched or branched alkyl radical containing1 to 8 carbon atoms, an unbranched or branched alkenyl radicalcontaining 2 to 8 carbon atoms, an unbranched or branched alkynylradical containing 2 to 8 carbon atoms, a cycloalkyl radical containing3 to 6 carbon atoms, a phenyl or α- or β-naphthyl radical optionallysubstituted with one or more atoms or radicals selected from halogenatoms, alkyl, alkenyl, alkynyl, aryl, aralkyl, alkoxy, alkylthio,aryloxy, arylthio, hydroxyl, hydroxyalkyl, mercaptor, formyl, acyl,acylamino, aroylamino, alkoxycarbonylamino, amino, alkylamino,dialkylamino, carboxyl, alkoxycarbonyl, carbamoyl, alkylcarbamoyl,dialkylcarbamoyl, cyano, nitro and trifluoromethyl radicals, or a5-membered aromatic heterocyclic containing one or more identical ordifferent hetero atoms selected from nitrogen, oxygen and sulphur atomsand optionally substituted with one or more identical or differentsubstituents selected from halogen atoms, alkyl, aryl, amino,alkylamino, dialkylamino, alkoxycarbonylamino, acyl, arylcarbonyl,cyano, carboxyl, carbamoyl, alkylcarbamoyl, dialkylcarbamoyl andalkoxycarbonyl radicals, with the proviso that, in the substituents ofthe phenyl, α- or β-naphthyl and aromatic heterocyclic radicals in thedefinitions of R₂ and R₃, the alkyl radicals and the alkyl portions ofthe other radicals contain 1 to 4 carbon atoms, and the alkenyl andalkynyl radicals contain 2 to 8 carbon atoms, and the aryl radicals arephenyl or α- or β-naphthyl radicals R₄ represents an alkoxy radicalcontaining 1 to 6 carbon atoms in an unbranched or branched chainsubstituted with at least one substituent selected from an alkylthioradical containing 1 to 4 carbon atoms, and R₅ represents an alkoxycontaining 1 to 6 carbon atoms in an unbranched or branched chainsubstituted with at least one substituent selected from an alkylthioradical containing 1 to 4 carbon atoms.
 16. A pharmaceutical compositionaccording to claim 7, wherein said on or more compatible andpharmacologically active compounds is present and is cisplatin.
 17. Apharmaceutical composition according to claim 16, wherein Z represents aradical of formula (II) in which R₁ represents a benzoyl radical or aradical R₂—O—CO— in which R₂ represents a tert-butyl radical, and R₃represents an alkyl radical containing 1 to 6 carbon atoms; an alkenylradical containing 2 to 6 carbon atoms; a cycloalkyl radical containing3 to 6 carbon atoms; a phenyl radical optionally substituted with one ormore identical or different atoms or radicals selected from halogenatoms, alkyl, alkoxy, dialkylamino, acylamino, alkoxycarbonylamino andtrifluoromethyl radicals; or a 2-furyl, 3-furyl, 2-thienyl, 3-thienyl,2-thiazolyl, 4-thiazolyl, or 5-thiazolyl radical.
 18. A pharmaceuticalcomposition according to claim 17, wherein Z represents a radical offormula (II) in which R₁ represents a benzoyl radical or a radicalR₂—O—CO— in which R₂ represents tert-butyl radical, R₃ represents anisobutyl, isobutenyl, butenyl, cyclohexyl, phenyl, 2-furyl, 3-furyl,2-thienyl, 3-thienyl, 2-thiazolyl, 4-thiazolyl or 5-thiazolyl radical,and R₄ and R₅, which may be identical or different, each represent amethoxy, ethoxy or propoxy radical.
 19. A pharmaceutical compositionaccording to claim 16, wherein when R₂ represents a 5-membered aromaticheterocyclic radical, said radical is a furyl or thienyl radical.
 20. Apharmaceutical composition comprising4α-acetoxy-2α-benzoyloxy-1β-hydroxy-5β,20-epoxy-7β,10β-dimethoxy-9-oxo-11-taxen-13α-yl(2R,3S)-3-tert-butoxycarbonylamino-2-hydroxy-3-phenylpropionateand cisplatin.
 21. A pharmaceutical composition comprising4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-10β-ethoxy-1β-hydroxy-7β-methoxy-9-oxo-11-taxen-13α-yl(2R,3S)-3-phenylpropionateand cisplatin.
 22. A pharmaceutical composition comprising4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-10β-(1-propyl)oxy-1β-hydroxy-7β-methoxy-9-oxo-11-taxen-13α-yl(2R,3S)-3-tert-butoxycarbonylamino-2-hydroxy-3-phenyl-propionate andcisplatin.
 23. A pharmaceutical composition comprising4α-acetoxy-2α-benzoyloxy-1β-hydroxy-5β,20-epoxy-7β,10β-dimethoxy-9-oxo-11-taxen-13α-yl(2R,3S)-3-tert-butoxycarbonylamino-2-hydroxy-3-phenylpropionatein combination with one or more pharmaceutically acceptable diluents oradjuvants and one or more compatible and pharmacologically activecompounds.
 24. A pharmaceutical composition comprising an ester of theformula (V):

wherein R₁ represents a benzoyl radical optionally substituted with oneor more identical or different atoms or radicals selected from halogenatoms, alkyl radicals containing 1 to 4 carbon atoms, alkoxy radicalscontaining 1 to 4 carbon atoms, and trifluoromethyl radicals, a thenoylradical, a furoyl radical, or a radical R₂—O—CO— in which R₂ representsan alkyl radical containing 1 to 8 carbon atoms, an alkenyl radicalcontaining 2 to 8 carbon atoms, an alkynyl radical containing 3 to 8carbon atoms, a cycloalkyl radical containing 3 to 6 carbon atoms, acycloalkenyl radical containing 4 to 6 carbon atoms or a bicycloalkylradical containing 7 to 10 carbon atoms, these radicals being optionallysubstituted with one or more substituents selected from halogen atoms;hydroxyl radicals; alkoxy radicals containing 1 to 4 carbon atoms;dialkylamino radicals in which each alkyl portion contains 1 to 4 carbonatoms; piperidino radicals; morpholino radicals; 1-piperazinyl radicalsoptionally substituted at position 4 with an alkyl radical containing 1to 4 carbon atoms or with a phenylalkyl radicals in which the alkylportion contains 1 to 4 carbon atoms; cycloalkyl radicals containing 3to 6 carbon atoms; cycloalkenyl radicals containing 4 to 6 carbon atoms;phenyl radicals optionally substituted with one or more atoms orradicals selected from halogen atoms, alkyl radicals containing 1 to 4carbon atoms and alkoxy radicals containing to 4 carbon atoms; cyanoradicals; carboxyl radicals; and alkoxycarbonyl radicals in which thealkyl portion contains 1 to 4 carbon atoms, a phenyl or α- or β-naphthylradical optionally substituted with one or more atoms or radicalsselected from halogen atoms; alkyl radicals containing 1 to 4 carbonatoms; and alkoxy radicals containing 1 to 4 carbon atoms, a 5-memberedaromatic heterocyclic radical, or a saturated heterocyclic radicalcontaining 4 to 6 carbon atoms, optionally substituted with one or morealkyl radicals containing 1 to 4 carbon atoms, R₃ represents anunbranched or branched alkyl radical containing 1 to 8 carbon atoms, anunbranched or branched alkenyl radical containing 2 to 8 carbon atoms,an unbranched or branched alkynyl radical containing 2 to 8 carbonatoms, cycloalkyl radical containing 3 to 6 carbon atoms, a phenyl or α-or β-naphthyl radical optionally substituted with one or more atoms orradicals selected from halogen atoms, alkyl, alkenyl, alkynyl, aryl,aralkyl, alkoxy, alkylthio, aryloxy, arylthio, hydroxy hydroxyalkyl,mercapto, formyl, acyl, acylamino, aroylamino, alkoxycarbonylamino,amino, alkylamino, dialkylamino, carboxyl, alkoxycarbonyl, carbamoyl,alkylcarbamoyl, dialkylcarbamoyl, cyano, nitro and trifluoromethylradicals, or a 5-membered aromatic heterocycle containing one or moreidentical or different hetero atoms selected from nitrogen, oxygen andsulphur atoms and optionally substituted with one or more identical ordifferent substituents selected from halogen atoms, alkyl, aryl, amino,alkylamino, dialkylamino, alkoxycarbonylamino, acyl, arylcarbonyl,cyano, carboxyl, carbamoyl, alkylcarbamoyl, dialkylcarbamoyl andalkoxycarbonyl radicals, with the proviso that, in the substituents ofthe phenyl, α- or β-naphthyl and aromatic heterocyclic radicals in thedefinitions of R₂ and R₃, the alkyl radicals and the alkyl portions ofthe other radicals contain 1 to 4 carbon atoms, and the alkenyl andalkynyl radicals contain 2 to 8 carbon atoms, and the aryl radicals arephenyl or α- or β-naphthyl radicals, R₄ represents an alkoxy radicalcontaining 1 to 6 carbon atoms in an unbranched or branched chain, R₅represents an alkoxy radical containing 1 to 6 carbon atoms in anunbranched or branched chain, and R₆ and R₇ each represents a hydrogenatom in combination with one or more pharmaceutically acceptablediluents or adjuvants and one or more compatible and pharmacologicallyactive compounds.
 25. A pharmaceutical composition according to claim24, wherein said one or more compatible and pharmacologically activecompounds is cisplatin.